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Fix for issue #40: Added support to render using premultiplied alpha

- added support to take screen shots
- added support to render to frame buffer using premultiplied alpha
- fixed spelling NVGaling -> NVGalign
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1 parent 51c7d9f commit ba3c0cbce1485bab9e6fc6d4f2a63b15043a52eb @memononen committed Feb 25, 2014
Showing with 723 additions and 21 deletions.
  1. +104 −0 example/demo.c
  2. +2 −0 example/demo.h
  3. +16 −2 example/example_gl2.c
  4. +16 −2 example/example_gl3.c
  5. +16 −2 example/example_gles2.c
  6. +16 −2 example/example_gles3.c
  7. +511 −0 example/stb_image_write.h
  8. +7 −3 src/nanovg.c
  9. +12 −4 src/nanovg.h
  10. +9 −2 src/nanovg_gl2.h
  11. +7 −2 src/nanovg_gl3.h
  12. +7 −2 src/nanovg_gl3buf.h
View
104 example/demo.c
@@ -7,6 +7,8 @@
#endif
#include <GLFW/glfw3.h>
#include "nanovg.h"
+#define STB_IMAGE_WRITE_IMPLEMENTATION
+#include "stb_image_write.h"
#ifdef _MSC_VER
@@ -850,3 +852,105 @@ void renderDemo(struct NVGcontext* vg, float mx, float my, float width, float he
nvgRestore(vg);
}
+static int mini(int a, int b) { return a < b ? a : b; }
+
+static void unpremultiplyAlpha(unsigned char* image, int w, int h, int stride)
+{
+ int x,y;
+
+ // Unpremultiply
+ for (y = 0; y < h; y++) {
+ unsigned char *row = &image[y*stride];
+ for (x = 0; x < w; x++) {
+ int r = row[0], g = row[1], b = row[2], a = row[3];
+ if (a != 0) {
+ row[0] = (int)mini(r*255/a, 255);
+ row[1] = (int)mini(g*255/a, 255);
+ row[2] = (int)mini(b*255/a, 255);
+ }
+ row += 4;
+ }
+ }
+
+ // Defringe
+ for (y = 0; y < h; y++) {
+ unsigned char *row = &image[y*stride];
+ for (x = 0; x < w; x++) {
+ int r = 0, g = 0, b = 0, a = row[3], n = 0;
+ if (a == 0) {
+ if (x-1 > 0 && row[-1] != 0) {
+ r += row[-4];
+ g += row[-3];
+ b += row[-2];
+ n++;
+ }
+ if (x+1 < w && row[7] != 0) {
+ r += row[4];
+ g += row[5];
+ b += row[6];
+ n++;
+ }
+ if (y-1 > 0 && row[-stride+3] != 0) {
+ r += row[-stride];
+ g += row[-stride+1];
+ b += row[-stride+2];
+ n++;
+ }
+ if (y+1 < h && row[stride+3] != 0) {
+ r += row[stride];
+ g += row[stride+1];
+ b += row[stride+2];
+ n++;
+ }
+ if (n > 0) {
+ row[0] = r/n;
+ row[1] = g/n;
+ row[2] = b/n;
+ }
+ }
+ row += 4;
+ }
+ }
+}
+
+static void setAlpha(unsigned char* image, int w, int h, int stride, unsigned char a)
+{
+ int x, y;
+ for (y = 0; y < h; y++) {
+ unsigned char* row = &image[y*stride];
+ for (x = 0; x < w; x++)
+ row[x*4+3] = a;
+ }
+}
+
+static void flipHorizontal(unsigned char* image, int w, int h, int stride)
+{
+ int i = 0, j = h-1, k;
+ while (i < j) {
+ unsigned char* ri = &image[i * stride];
+ unsigned char* rj = &image[j * stride];
+ for (k = 0; k < w*4; k++) {
+ unsigned char t = ri[k];
+ ri[k] = rj[k];
+ rj[k] = t;
+ }
+ i++;
+ j--;
+ }
+}
+
+void saveScreenShot(int w, int h, int premult, const char* name)
+{
+ unsigned char* image = (unsigned char*)malloc(w*h*4);
+ if (image == NULL)
+ return;
+ glReadPixels(0, 0, w, h, GL_RGBA, GL_UNSIGNED_BYTE, image);
+ if (premult)
+ unpremultiplyAlpha(image, w, h, w*4);
+ else
+ setAlpha(image, w, h, w*4, 255);
+ flipHorizontal(image, w, h, w*4);
+ stbi_write_png(name, w, h, 4, image, w*4);
+ free(image);
+}
+
View
2 example/demo.h
@@ -16,6 +16,8 @@ int loadDemoData(struct NVGcontext* vg, struct DemoData* data);
void freeDemoData(struct NVGcontext* vg, struct DemoData* data);
void renderDemo(struct NVGcontext* vg, float mx, float my, float width, float height, float t, int blowup, struct DemoData* data);
+void saveScreenShot(int w, int h, int premult, const char* name);
+
#ifdef __cplusplus
}
#endif
View
18 example/example_gl2.c
@@ -34,6 +34,8 @@ void errorcb(int error, const char* desc)
}
int blowup = 0;
+int screenshot = 0;
+int premult = 0;
static void key(GLFWwindow* window, int key, int scancode, int action, int mods)
{
@@ -43,6 +45,10 @@ static void key(GLFWwindow* window, int key, int scancode, int action, int mods)
glfwSetWindowShouldClose(window, GL_TRUE);
if (key == GLFW_KEY_SPACE && action == GLFW_PRESS)
blowup = !blowup;
+ if (key == GLFW_KEY_S && action == GLFW_PRESS)
+ screenshot = 1;
+ if (key == GLFW_KEY_P && action == GLFW_PRESS)
+ premult = !premult;
}
int main()
@@ -124,15 +130,18 @@ int main()
// Update and render
glViewport(0, 0, fbWidth, fbHeight);
- glClearColor(0.3f, 0.3f, 0.32f, 1.0f);
+ if (premult)
+ glClearColor(0,0,0,0);
+ else
+ glClearColor(0.3f, 0.3f, 0.32f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT|GL_STENCIL_BUFFER_BIT);
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glEnable(GL_CULL_FACE);
glDisable(GL_DEPTH_TEST);
- nvgBeginFrame(vg, winWidth, winHeight, pxRatio);
+ nvgBeginFrame(vg, winWidth, winHeight, pxRatio, premult ? NVG_PREMULTIPLIED_ALPHA : NVG_STRAIGHT_ALPHA);
renderDemo(vg, mx,my, winWidth,winHeight, t, blowup, &data);
renderGraph(vg, 5,5, &fps);
@@ -141,6 +150,11 @@ int main()
glEnable(GL_DEPTH_TEST);
+ if (screenshot) {
+ screenshot = 0;
+ saveScreenShot(fbWidth, fbHeight, premult, "dump.png");
+ }
+
glfwSwapBuffers(window);
glfwPollEvents();
}
View
18 example/example_gl3.c
@@ -38,6 +38,8 @@ void errorcb(int error, const char* desc)
}
int blowup = 0;
+int screenshot = 0;
+int premult = 0;
static void key(GLFWwindow* window, int key, int scancode, int action, int mods)
{
@@ -47,6 +49,10 @@ static void key(GLFWwindow* window, int key, int scancode, int action, int mods)
glfwSetWindowShouldClose(window, GL_TRUE);
if (key == GLFW_KEY_SPACE && action == GLFW_PRESS)
blowup = !blowup;
+ if (key == GLFW_KEY_S && action == GLFW_PRESS)
+ screenshot = 1;
+ if (key == GLFW_KEY_P && action == GLFW_PRESS)
+ premult = !premult;
}
int main()
@@ -139,15 +145,18 @@ int main()
// Update and render
glViewport(0, 0, fbWidth, fbHeight);
- glClearColor(0.3f, 0.3f, 0.32f, 1.0f);
+ if (premult)
+ glClearColor(0,0,0,0);
+ else
+ glClearColor(0.3f, 0.3f, 0.32f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT|GL_STENCIL_BUFFER_BIT);
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glEnable(GL_CULL_FACE);
glDisable(GL_DEPTH_TEST);
- nvgBeginFrame(vg, winWidth, winHeight, pxRatio);
+ nvgBeginFrame(vg, winWidth, winHeight, pxRatio, premult ? NVG_PREMULTIPLIED_ALPHA : NVG_STRAIGHT_ALPHA);
renderDemo(vg, mx,my, winWidth,winHeight, t, blowup, &data);
@@ -171,6 +180,11 @@ int main()
for (i = 0; i < n; i++)
updateGraph(&gpuGraph, gpuTimes[i]);
+ if (screenshot) {
+ screenshot = 0;
+ saveScreenShot(fbWidth, fbHeight, premult, "dump.png");
+ }
+
glfwSwapBuffers(window);
glfwPollEvents();
}
View
18 example/example_gles2.c
@@ -32,6 +32,8 @@ void errorcb(int error, const char* desc)
}
int blowup = 0;
+int screenshot = 0;
+int premult = 0;
static void key(GLFWwindow* window, int key, int scancode, int action, int mods)
{
@@ -41,6 +43,10 @@ static void key(GLFWwindow* window, int key, int scancode, int action, int mods)
glfwSetWindowShouldClose(window, GL_TRUE);
if (key == GLFW_KEY_SPACE && action == GLFW_PRESS)
blowup = !blowup;
+ if (key == GLFW_KEY_S && action == GLFW_PRESS)
+ screenshot = 1;
+ if (key == GLFW_KEY_P && action == GLFW_PRESS)
+ premult = !premult;
}
int main()
@@ -109,21 +115,29 @@ int main()
// Update and render
glViewport(0, 0, fbWidth, fbHeight);
- glClearColor(0.3f, 0.3f, 0.32f, 1.0f);
+ if (premult)
+ glClearColor(0,0,0,0);
+ else
+ glClearColor(0.3f, 0.3f, 0.32f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT|GL_STENCIL_BUFFER_BIT);
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glEnable(GL_CULL_FACE);
glDisable(GL_DEPTH_TEST);
- nvgBeginFrame(vg, winWidth, winHeight, pxRatio);
+ nvgBeginFrame(vg, winWidth, winHeight, pxRatio, premult ? NVG_PREMULTIPLIED_ALPHA : NVG_STRAIGHT_ALPHA);
renderDemo(vg, mx,my, winWidth,winHeight, t, blowup, &data);
renderGraph(vg, 5,5, &fps);
nvgEndFrame(vg);
+ if (screenshot) {
+ screenshot = 0;
+ saveScreenShot(fbWidth, fbHeight, premult, "dump.png");
+ }
+
glEnable(GL_DEPTH_TEST);
glfwSwapBuffers(window);
View
18 example/example_gles3.c
@@ -32,6 +32,8 @@ void errorcb(int error, const char* desc)
}
int blowup = 0;
+int screenshot = 0;
+int premult = 0;
static void key(GLFWwindow* window, int key, int scancode, int action, int mods)
{
@@ -41,6 +43,10 @@ static void key(GLFWwindow* window, int key, int scancode, int action, int mods)
glfwSetWindowShouldClose(window, GL_TRUE);
if (key == GLFW_KEY_SPACE && action == GLFW_PRESS)
blowup = !blowup;
+ if (key == GLFW_KEY_S && action == GLFW_PRESS)
+ screenshot = 1;
+ if (key == GLFW_KEY_P && action == GLFW_PRESS)
+ premult = !premult;
}
int main()
@@ -109,15 +115,18 @@ int main()
// Update and render
glViewport(0, 0, fbWidth, fbHeight);
- glClearColor(0.3f, 0.3f, 0.32f, 1.0f);
+ if (premult)
+ glClearColor(0,0,0,0);
+ else
+ glClearColor(0.3f, 0.3f, 0.32f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT|GL_STENCIL_BUFFER_BIT);
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glEnable(GL_CULL_FACE);
glDisable(GL_DEPTH_TEST);
- nvgBeginFrame(vg, winWidth, winHeight, pxRatio);
+ nvgBeginFrame(vg, winWidth, winHeight, pxRatio, premult ? NVG_PREMULTIPLIED_ALPHA : NVG_STRAIGHT_ALPHA);
renderDemo(vg, mx,my, winWidth,winHeight, t, blowup, &data);
renderGraph(vg, 5,5, &fps);
@@ -126,6 +135,11 @@ int main()
glEnable(GL_DEPTH_TEST);
+ if (screenshot) {
+ screenshot = 0;
+ saveScreenShot(fbWidth, fbHeight, premult, "dump.png");
+ }
+
glfwSwapBuffers(window);
glfwPollEvents();
}
View
511 example/stb_image_write.h
@@ -0,0 +1,511 @@
+/* stbiw-0.92 - public domain - http://nothings.org/stb/stb_image_write.h
+ writes out PNG/BMP/TGA images to C stdio - Sean Barrett 2010
+ no warranty implied; use at your own risk
+
+
+Before including,
+
+ #define STB_IMAGE_WRITE_IMPLEMENTATION
+
+in the file that you want to have the implementation.
+
+
+ABOUT:
+
+ This header file is a library for writing images to C stdio. It could be
+ adapted to write to memory or a general streaming interface; let me know.
+
+ The PNG output is not optimal; it is 20-50% larger than the file
+ written by a decent optimizing implementation. This library is designed
+ for source code compactness and simplicitly, not optimal image file size
+ or run-time performance.
+
+USAGE:
+
+ There are three functions, one for each image file format:
+
+ int stbi_write_png(char const *filename, int w, int h, int comp, const void *data, int stride_in_bytes);
+ int stbi_write_bmp(char const *filename, int w, int h, int comp, const void *data);
+ int stbi_write_tga(char const *filename, int w, int h, int comp, const void *data);
+
+ Each function returns 0 on failure and non-0 on success.
+
+ The functions create an image file defined by the parameters. The image
+ is a rectangle of pixels stored from left-to-right, top-to-bottom.
+ Each pixel contains 'comp' channels of data stored interleaved with 8-bits
+ per channel, in the following order: 1=Y, 2=YA, 3=RGB, 4=RGBA. (Y is
+ monochrome color.) The rectangle is 'w' pixels wide and 'h' pixels tall.
+ The *data pointer points to the first byte of the top-left-most pixel.
+ For PNG, "stride_in_bytes" is the distance in bytes from the first byte of
+ a row of pixels to the first byte of the next row of pixels.
+
+ PNG creates output files with the same number of components as the input.
+ The BMP and TGA formats expand Y to RGB in the file format. BMP does not
+ output alpha.
+
+ PNG supports writing rectangles of data even when the bytes storing rows of
+ data are not consecutive in memory (e.g. sub-rectangles of a larger image),
+ by supplying the stride between the beginning of adjacent rows. The other
+ formats do not. (Thus you cannot write a native-format BMP through the BMP
+ writer, both because it is in BGR order and because it may have padding
+ at the end of the line.)
+*/
+
+#ifndef INCLUDE_STB_IMAGE_WRITE_H
+#define INCLUDE_STB_IMAGE_WRITE_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern int stbi_write_png(char const *filename, int w, int h, int comp, const void *data, int stride_in_bytes);
+extern int stbi_write_bmp(char const *filename, int w, int h, int comp, const void *data);
+extern int stbi_write_tga(char const *filename, int w, int h, int comp, const void *data);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif//INCLUDE_STB_IMAGE_WRITE_H
+
+#ifdef STB_IMAGE_WRITE_IMPLEMENTATION
+
+#include <stdarg.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+
+typedef unsigned int stbiw_uint32;
+typedef int stb_image_write_test[sizeof(stbiw_uint32)==4 ? 1 : -1];
+
+static void writefv(FILE *f, const char *fmt, va_list v)
+{
+ while (*fmt) {
+ switch (*fmt++) {
+ case ' ': break;
+ case '1': { unsigned char x = (unsigned char) va_arg(v, int); fputc(x,f); break; }
+ case '2': { int x = va_arg(v,int); unsigned char b[2];
+ b[0] = (unsigned char) x; b[1] = (unsigned char) (x>>8);
+ fwrite(b,2,1,f); break; }
+ case '4': { stbiw_uint32 x = va_arg(v,int); unsigned char b[4];
+ b[0]=(unsigned char)x; b[1]=(unsigned char)(x>>8);
+ b[2]=(unsigned char)(x>>16); b[3]=(unsigned char)(x>>24);
+ fwrite(b,4,1,f); break; }
+ default:
+ assert(0);
+ return;
+ }
+ }
+}
+
+static void write3(FILE *f, unsigned char a, unsigned char b, unsigned char c)
+{
+ unsigned char arr[3];
+ arr[0] = a, arr[1] = b, arr[2] = c;
+ fwrite(arr, 3, 1, f);
+}
+
+static void write_pixels(FILE *f, int rgb_dir, int vdir, int x, int y, int comp, void *data, int write_alpha, int scanline_pad)
+{
+ unsigned char bg[3] = { 255, 0, 255}, px[3];
+ stbiw_uint32 zero = 0;
+ int i,j,k, j_end;
+
+ if (y <= 0)
+ return;
+
+ if (vdir < 0)
+ j_end = -1, j = y-1;
+ else
+ j_end = y, j = 0;
+
+ for (; j != j_end; j += vdir) {
+ for (i=0; i < x; ++i) {
+ unsigned char *d = (unsigned char *) data + (j*x+i)*comp;
+ if (write_alpha < 0)
+ fwrite(&d[comp-1], 1, 1, f);
+ switch (comp) {
+ case 1:
+ case 2: write3(f, d[0],d[0],d[0]);
+ break;
+ case 4:
+ if (!write_alpha) {
+ // composite against pink background
+ for (k=0; k < 3; ++k)
+ px[k] = bg[k] + ((d[k] - bg[k]) * d[3])/255;
+ write3(f, px[1-rgb_dir],px[1],px[1+rgb_dir]);
+ break;
+ }
+ /* FALLTHROUGH */
+ case 3:
+ write3(f, d[1-rgb_dir],d[1],d[1+rgb_dir]);
+ break;
+ }
+ if (write_alpha > 0)
+ fwrite(&d[comp-1], 1, 1, f);
+ }
+ fwrite(&zero,scanline_pad,1,f);
+ }
+}
+
+static int outfile(char const *filename, int rgb_dir, int vdir, int x, int y, int comp, void *data, int alpha, int pad, const char *fmt, ...)
+{
+ FILE *f;
+ if (y < 0 || x < 0) return 0;
+ f = fopen(filename, "wb");
+ if (f) {
+ va_list v;
+ va_start(v, fmt);
+ writefv(f, fmt, v);
+ va_end(v);
+ write_pixels(f,rgb_dir,vdir,x,y,comp,data,alpha,pad);
+ fclose(f);
+ }
+ return f != NULL;
+}
+
+int stbi_write_bmp(char const *filename, int x, int y, int comp, const void *data)
+{
+ int pad = (-x*3) & 3;
+ return outfile(filename,-1,-1,x,y,comp,(void *) data,0,pad,
+ "11 4 22 4" "4 44 22 444444",
+ 'B', 'M', 14+40+(x*3+pad)*y, 0,0, 14+40, // file header
+ 40, x,y, 1,24, 0,0,0,0,0,0); // bitmap header
+}
+
+int stbi_write_tga(char const *filename, int x, int y, int comp, const void *data)
+{
+ int has_alpha = !(comp & 1);
+ return outfile(filename, -1,-1, x, y, comp, (void *) data, has_alpha, 0,
+ "111 221 2222 11", 0,0,2, 0,0,0, 0,0,x,y, 24+8*has_alpha, 8*has_alpha);
+}
+
+// stretchy buffer; stbi__sbpush() == vector<>::push_back() -- stbi__sbcount() == vector<>::size()
+#define stbi__sbraw(a) ((int *) (a) - 2)
+#define stbi__sbm(a) stbi__sbraw(a)[0]
+#define stbi__sbn(a) stbi__sbraw(a)[1]
+
+#define stbi__sbneedgrow(a,n) ((a)==0 || stbi__sbn(a)+n >= stbi__sbm(a))
+#define stbi__sbmaybegrow(a,n) (stbi__sbneedgrow(a,(n)) ? stbi__sbgrow(a,n) : 0)
+#define stbi__sbgrow(a,n) stbi__sbgrowf((void **) &(a), (n), sizeof(*(a)))
+
+#define stbi__sbpush(a, v) (stbi__sbmaybegrow(a,1), (a)[stbi__sbn(a)++] = (v))
+#define stbi__sbcount(a) ((a) ? stbi__sbn(a) : 0)
+#define stbi__sbfree(a) ((a) ? free(stbi__sbraw(a)),0 : 0)
+
+static void *stbi__sbgrowf(void **arr, int increment, int itemsize)
+{
+ int m = *arr ? 2*stbi__sbm(*arr)+increment : increment+1;
+ void *p = realloc(*arr ? stbi__sbraw(*arr) : 0, itemsize * m + sizeof(int)*2);
+ assert(p);
+ if (p) {
+ if (!*arr) ((int *) p)[1] = 0;
+ *arr = (void *) ((int *) p + 2);
+ stbi__sbm(*arr) = m;
+ }
+ return *arr;
+}
+
+static unsigned char *stbi__zlib_flushf(unsigned char *data, unsigned int *bitbuffer, int *bitcount)
+{
+ while (*bitcount >= 8) {
+ stbi__sbpush(data, (unsigned char) *bitbuffer);
+ *bitbuffer >>= 8;
+ *bitcount -= 8;
+ }
+ return data;
+}
+
+static int stbi__zlib_bitrev(int code, int codebits)
+{
+ int res=0;
+ while (codebits--) {
+ res = (res << 1) | (code & 1);
+ code >>= 1;
+ }
+ return res;
+}
+
+static unsigned int stbi__zlib_countm(unsigned char *a, unsigned char *b, int limit)
+{
+ int i;
+ for (i=0; i < limit && i < 258; ++i)
+ if (a[i] != b[i]) break;
+ return i;
+}
+
+static unsigned int stbi__zhash(unsigned char *data)
+{
+ stbiw_uint32 hash = data[0] + (data[1] << 8) + (data[2] << 16);
+ hash ^= hash << 3;
+ hash += hash >> 5;
+ hash ^= hash << 4;
+ hash += hash >> 17;
+ hash ^= hash << 25;
+ hash += hash >> 6;
+ return hash;
+}
+
+#define stbi__zlib_flush() (out = stbi__zlib_flushf(out, &bitbuf, &bitcount))
+#define stbi__zlib_add(code,codebits) \
+ (bitbuf |= (code) << bitcount, bitcount += (codebits), stbi__zlib_flush())
+#define stbi__zlib_huffa(b,c) stbi__zlib_add(stbi__zlib_bitrev(b,c),c)
+// default huffman tables
+#define stbi__zlib_huff1(n) stbi__zlib_huffa(0x30 + (n), 8)
+#define stbi__zlib_huff2(n) stbi__zlib_huffa(0x190 + (n)-144, 9)
+#define stbi__zlib_huff3(n) stbi__zlib_huffa(0 + (n)-256,7)
+#define stbi__zlib_huff4(n) stbi__zlib_huffa(0xc0 + (n)-280,8)
+#define stbi__zlib_huff(n) ((n) <= 143 ? stbi__zlib_huff1(n) : (n) <= 255 ? stbi__zlib_huff2(n) : (n) <= 279 ? stbi__zlib_huff3(n) : stbi__zlib_huff4(n))
+#define stbi__zlib_huffb(n) ((n) <= 143 ? stbi__zlib_huff1(n) : stbi__zlib_huff2(n))
+
+#define stbi__ZHASH 16384
+
+unsigned char * stbi_zlib_compress(unsigned char *data, int data_len, int *out_len, int quality)
+{
+ static unsigned short lengthc[] = { 3,4,5,6,7,8,9,10,11,13,15,17,19,23,27,31,35,43,51,59,67,83,99,115,131,163,195,227,258, 259 };
+ static unsigned char lengtheb[]= { 0,0,0,0,0,0,0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0 };
+ static unsigned short distc[] = { 1,2,3,4,5,7,9,13,17,25,33,49,65,97,129,193,257,385,513,769,1025,1537,2049,3073,4097,6145,8193,12289,16385,24577, 32768 };
+ static unsigned char disteb[] = { 0,0,0,0,1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13 };
+ unsigned int bitbuf=0;
+ int i,j, bitcount=0;
+ unsigned char *out = NULL;
+ unsigned char **hash_table[stbi__ZHASH]; // 64KB on the stack!
+ if (quality < 5) quality = 5;
+
+ stbi__sbpush(out, 0x78); // DEFLATE 32K window
+ stbi__sbpush(out, 0x5e); // FLEVEL = 1
+ stbi__zlib_add(1,1); // BFINAL = 1
+ stbi__zlib_add(1,2); // BTYPE = 1 -- fixed huffman
+
+ for (i=0; i < stbi__ZHASH; ++i)
+ hash_table[i] = NULL;
+
+ i=0;
+ while (i < data_len-3) {
+ // hash next 3 bytes of data to be compressed
+ int h = stbi__zhash(data+i)&(stbi__ZHASH-1), best=3;
+ unsigned char *bestloc = 0;
+ unsigned char **hlist = hash_table[h];
+ int n = stbi__sbcount(hlist);
+ for (j=0; j < n; ++j) {
+ if (hlist[j]-data > i-32768) { // if entry lies within window
+ int d = stbi__zlib_countm(hlist[j], data+i, data_len-i);
+ if (d >= best) best=d,bestloc=hlist[j];
+ }
+ }
+ // when hash table entry is too long, delete half the entries
+ if (hash_table[h] && stbi__sbn(hash_table[h]) == 2*quality) {
+ memcpy(hash_table[h], hash_table[h]+quality, sizeof(hash_table[h][0])*quality);
+ stbi__sbn(hash_table[h]) = quality;
+ }
+ stbi__sbpush(hash_table[h],data+i);
+
+ if (bestloc) {
+ // "lazy matching" - check match at *next* byte, and if it's better, do cur byte as literal
+ h = stbi__zhash(data+i+1)&(stbi__ZHASH-1);
+ hlist = hash_table[h];
+ n = stbi__sbcount(hlist);
+ for (j=0; j < n; ++j) {
+ if (hlist[j]-data > i-32767) {
+ int e = stbi__zlib_countm(hlist[j], data+i+1, data_len-i-1);
+ if (e > best) { // if next match is better, bail on current match
+ bestloc = NULL;
+ break;
+ }
+ }
+ }
+ }
+
+ if (bestloc) {
+ int d = data+i - bestloc; // distance back
+ assert(d <= 32767 && best <= 258);
+ for (j=0; best > lengthc[j+1]-1; ++j);
+ stbi__zlib_huff(j+257);
+ if (lengtheb[j]) stbi__zlib_add(best - lengthc[j], lengtheb[j]);
+ for (j=0; d > distc[j+1]-1; ++j);
+ stbi__zlib_add(stbi__zlib_bitrev(j,5),5);
+ if (disteb[j]) stbi__zlib_add(d - distc[j], disteb[j]);
+ i += best;
+ } else {
+ stbi__zlib_huffb(data[i]);
+ ++i;
+ }
+ }
+ // write out final bytes
+ for (;i < data_len; ++i)
+ stbi__zlib_huffb(data[i]);
+ stbi__zlib_huff(256); // end of block
+ // pad with 0 bits to byte boundary
+ while (bitcount)
+ stbi__zlib_add(0,1);
+
+ for (i=0; i < stbi__ZHASH; ++i)
+ (void) stbi__sbfree(hash_table[i]);
+
+ {
+ // compute adler32 on input
+ unsigned int i=0, s1=1, s2=0, blocklen = data_len % 5552;
+ int j=0;
+ while (j < data_len) {
+ for (i=0; i < blocklen; ++i) s1 += data[j+i], s2 += s1;
+ s1 %= 65521, s2 %= 65521;
+ j += blocklen;
+ blocklen = 5552;
+ }
+ stbi__sbpush(out, (unsigned char) (s2 >> 8));
+ stbi__sbpush(out, (unsigned char) s2);
+ stbi__sbpush(out, (unsigned char) (s1 >> 8));
+ stbi__sbpush(out, (unsigned char) s1);
+ }
+ *out_len = stbi__sbn(out);
+ // make returned pointer freeable
+ memmove(stbi__sbraw(out), out, *out_len);
+ return (unsigned char *) stbi__sbraw(out);
+}
+
+unsigned int stbi__crc32(unsigned char *buffer, int len)
+{
+ static unsigned int crc_table[256];
+ unsigned int crc = ~0u;
+ int i,j;
+ if (crc_table[1] == 0)
+ for(i=0; i < 256; i++)
+ for (crc_table[i]=i, j=0; j < 8; ++j)
+ crc_table[i] = (crc_table[i] >> 1) ^ (crc_table[i] & 1 ? 0xedb88320 : 0);
+ for (i=0; i < len; ++i)
+ crc = (crc >> 8) ^ crc_table[buffer[i] ^ (crc & 0xff)];
+ return ~crc;
+}
+
+#define stbi__wpng4(o,a,b,c,d) ((o)[0]=(unsigned char)(a),(o)[1]=(unsigned char)(b),(o)[2]=(unsigned char)(c),(o)[3]=(unsigned char)(d),(o)+=4)
+#define stbi__wp32(data,v) stbi__wpng4(data, (v)>>24,(v)>>16,(v)>>8,(v));
+#define stbi__wptag(data,s) stbi__wpng4(data, s[0],s[1],s[2],s[3])
+
+static void stbi__wpcrc(unsigned char **data, int len)
+{
+ unsigned int crc = stbi__crc32(*data - len - 4, len+4);
+ stbi__wp32(*data, crc);
+}
+
+static unsigned char stbi__paeth(int a, int b, int c)
+{
+ int p = a + b - c, pa = abs(p-a), pb = abs(p-b), pc = abs(p-c);
+ if (pa <= pb && pa <= pc) return (unsigned char) a;
+ if (pb <= pc) return (unsigned char) b;
+ return (unsigned char) c;
+}
+
+unsigned char *stbi_write_png_to_mem(unsigned char *pixels, int stride_bytes, int x, int y, int n, int *out_len)
+{
+ int ctype[5] = { -1, 0, 4, 2, 6 };
+ unsigned char sig[8] = { 137,80,78,71,13,10,26,10 };
+ unsigned char *out,*o, *filt, *zlib;
+ signed char *line_buffer;
+ int i,j,k,p,zlen;
+
+ if (stride_bytes == 0)
+ stride_bytes = x * n;
+
+ filt = (unsigned char *) malloc((x*n+1) * y); if (!filt) return 0;
+ line_buffer = (signed char *) malloc(x * n); if (!line_buffer) { free(filt); return 0; }
+ for (j=0; j < y; ++j) {
+ static int mapping[] = { 0,1,2,3,4 };
+ static int firstmap[] = { 0,1,0,5,6 };
+ int *mymap = j ? mapping : firstmap;
+ int best = 0, bestval = 0x7fffffff;
+ for (p=0; p < 2; ++p) {
+ for (k= p?best:0; k < 5; ++k) {
+ int type = mymap[k],est=0;
+ unsigned char *z = pixels + stride_bytes*j;
+ for (i=0; i < n; ++i)
+ switch (type) {
+ case 0: line_buffer[i] = z[i]; break;
+ case 1: line_buffer[i] = z[i]; break;
+ case 2: line_buffer[i] = z[i] - z[i-stride_bytes]; break;
+ case 3: line_buffer[i] = z[i] - (z[i-stride_bytes]>>1); break;
+ case 4: line_buffer[i] = (signed char) (z[i] - stbi__paeth(0,z[i-stride_bytes],0)); break;
+ case 5: line_buffer[i] = z[i]; break;
+ case 6: line_buffer[i] = z[i]; break;
+ }
+ for (i=n; i < x*n; ++i) {
+ switch (type) {
+ case 0: line_buffer[i] = z[i]; break;
+ case 1: line_buffer[i] = z[i] - z[i-n]; break;
+ case 2: line_buffer[i] = z[i] - z[i-stride_bytes]; break;
+ case 3: line_buffer[i] = z[i] - ((z[i-n] + z[i-stride_bytes])>>1); break;
+ case 4: line_buffer[i] = z[i] - stbi__paeth(z[i-n], z[i-stride_bytes], z[i-stride_bytes-n]); break;
+ case 5: line_buffer[i] = z[i] - (z[i-n]>>1); break;
+ case 6: line_buffer[i] = z[i] - stbi__paeth(z[i-n], 0,0); break;
+ }
+ }
+ if (p) break;
+ for (i=0; i < x*n; ++i)
+ est += abs((signed char) line_buffer[i]);
+ if (est < bestval) { bestval = est; best = k; }
+ }
+ }
+ // when we get here, best contains the filter type, and line_buffer contains the data
+ filt[j*(x*n+1)] = (unsigned char) best;
+ memcpy(filt+j*(x*n+1)+1, line_buffer, x*n);
+ }
+ free(line_buffer);
+ zlib = stbi_zlib_compress(filt, y*( x*n+1), &zlen, 8); // increase 8 to get smaller but use more memory
+ free(filt);
+ if (!zlib) return 0;
+
+ // each tag requires 12 bytes of overhead
+ out = (unsigned char *) malloc(8 + 12+13 + 12+zlen + 12);
+ if (!out) return 0;
+ *out_len = 8 + 12+13 + 12+zlen + 12;
+
+ o=out;
+ memcpy(o,sig,8); o+= 8;
+ stbi__wp32(o, 13); // header length
+ stbi__wptag(o, "IHDR");
+ stbi__wp32(o, x);
+ stbi__wp32(o, y);
+ *o++ = 8;
+ *o++ = (unsigned char) ctype[n];
+ *o++ = 0;
+ *o++ = 0;
+ *o++ = 0;
+ stbi__wpcrc(&o,13);
+
+ stbi__wp32(o, zlen);
+ stbi__wptag(o, "IDAT");
+ memcpy(o, zlib, zlen); o += zlen; free(zlib);
+ stbi__wpcrc(&o, zlen);
+
+ stbi__wp32(o,0);
+ stbi__wptag(o, "IEND");
+ stbi__wpcrc(&o,0);
+
+ assert(o == out + *out_len);
+
+ return out;
+}
+
+int stbi_write_png(char const *filename, int x, int y, int comp, const void *data, int stride_bytes)
+{
+ FILE *f;
+ int len;
+ unsigned char *png = stbi_write_png_to_mem((unsigned char *) data, stride_bytes, x, y, comp, &len);
+ if (!png) return 0;
+ f = fopen(filename, "wb");
+ if (!f) { free(png); return 0; }
+ fwrite(png, 1, len, f);
+ fclose(f);
+ free(png);
+ return 1;
+}
+#endif // STB_IMAGE_WRITE_IMPLEMENTATION
+
+/* Revision history
+
+ 0.92 (2010-08-01)
+ casts to unsigned char to fix warnings
+ 0.91 (2010-07-17)
+ first public release
+ 0.90 first internal release
+*/
View
10 src/nanovg.c
@@ -107,6 +107,7 @@ struct NVGcontext {
float devicePxRatio;
struct FONScontext* fs;
int fontImage;
+ int alphaBlend;
int drawCallCount;
int fillTriCount;
int strokeTriCount;
@@ -200,6 +201,8 @@ struct NVGcontext* nvgCreateInternal(struct NVGparams* params)
ctx->ncommands = 0;
ctx->ccommands = NVG_INIT_PATH_SIZE;
+ ctx->alphaBlend = NVG_STRAIGHT_ALPHA;
+
ctx->cache = nvg__allocPathCache();
if (ctx->cache == NULL) goto error;
@@ -249,7 +252,7 @@ void nvgDeleteInternal(struct NVGcontext* ctx)
free(ctx);
}
-void nvgBeginFrame(struct NVGcontext* ctx, int windowWidth, int windowHeight, float devicePixelRatio)
+void nvgBeginFrame(struct NVGcontext* ctx, int windowWidth, int windowHeight, float devicePixelRatio, int alphaBlend)
{
/* printf("Tris: draws:%d fill:%d stroke:%d text:%d TOT:%d\n",
ctx->drawCallCount, ctx->fillTriCount, ctx->strokeTriCount, ctx->textTriCount,
@@ -260,8 +263,9 @@ void nvgBeginFrame(struct NVGcontext* ctx, int windowWidth, int windowHeight, fl
nvgReset(ctx);
nvg__setDevicePixelRatio(ctx, devicePixelRatio);
+ ctx->alphaBlend = alphaBlend;
- ctx->params.renderViewport(ctx->params.userPtr, windowWidth, windowHeight);
+ ctx->params.renderViewport(ctx->params.userPtr, windowWidth, windowHeight, ctx->alphaBlend);
ctx->drawCallCount = 0;
ctx->fillTriCount = 0;
@@ -271,7 +275,7 @@ void nvgBeginFrame(struct NVGcontext* ctx, int windowWidth, int windowHeight, fl
void nvgEndFrame(struct NVGcontext* ctx)
{
- ctx->params.renderFlush(ctx->params.userPtr);
+ ctx->params.renderFlush(ctx->params.userPtr, ctx->alphaBlend);
}
unsigned int nvgRGB(unsigned char r, unsigned char g, unsigned char b)
View
16 src/nanovg.h
@@ -62,7 +62,7 @@ enum NVGpatternRepeat {
NVG_REPEATY = 0x02, // Repeat image pattern in Y direction
};
-enum NVGaling {
+enum NVGalign {
// Horizontal align
NVG_ALIGN_LEFT = 1<<0, // Default, align text horizontally to left.
NVG_ALIGN_CENTER = 1<<1, // Align text horizontally to center.
@@ -74,6 +74,10 @@ enum NVGaling {
NVG_ALIGN_BASELINE = 1<<6, // Default, align text vertically to baseline.
};
+enum NVGalpha {
+ NVG_STRAIGHT_ALPHA,
+ NVG_PREMULTIPLIED_ALPHA,
+};
// Begin drawing a new frame
// Calls to nanovg drawing API should be wrapped in nvgBeginFrame() & nvgEndFrame()
@@ -83,7 +87,11 @@ enum NVGaling {
// For example, GLFW returns two dimension for an opened window: window size and
// frame buffer size. In that case you would set windowWidth/Height to the window size
// devicePixelRatio to: frameBufferWidth / windowWidth.
-void nvgBeginFrame(struct NVGcontext* ctx, int windowWidth, int windowHeight, float devicePixelRatio);
+// AlphaBlend controls if drawing the shapes to the render target should be done using straight or
+// premultiplied alpha. If rendering directly to framebuffer you probably want to use NVG_STRAIGHT_ALPHA,
+// if rendering to texture which should contain transparent regions NVG_PREMULTIPLIED_ALPHA is the
+// right choice.
+void nvgBeginFrame(struct NVGcontext* ctx, int windowWidth, int windowHeight, float devicePixelRatio, int alphaBlend);
// Ends drawing flushing remaining render state.
void nvgEndFrame(struct NVGcontext* ctx);
@@ -430,8 +438,8 @@ struct NVGparams {
int (*renderDeleteTexture)(void* uptr, int image);
int (*renderUpdateTexture)(void* uptr, int image, int x, int y, int w, int h, const unsigned char* data);
int (*renderGetTextureSize)(void* uptr, int image, int* w, int* h);
- void (*renderViewport)(void* uptr, int width, int height);
- void (*renderFlush)(void* uptr);
+ void (*renderViewport)(void* uptr, int width, int height, int alphaBlend);
+ void (*renderFlush)(void* uptr, int alphaBlend);
void (*renderFill)(void* uptr, struct NVGpaint* paint, struct NVGscissor* scissor, const float* bounds, const struct NVGpath* paths, int npaths);
void (*renderStroke)(void* uptr, struct NVGpaint* paint, struct NVGscissor* scissor, float strokeWidth, const struct NVGpath* paths, int npaths);
void (*renderTriangles)(void* uptr, struct NVGpaint* paint, struct NVGscissor* scissor, const struct NVGvertex* verts, int nverts);
View
11 src/nanovg_gl2.h
@@ -626,17 +626,24 @@ static int glnvg__setupPaint(struct GLNVGcontext* gl, struct NVGpaint* paint, st
return 1;
}
-static void glnvg__renderViewport(void* uptr, int width, int height)
+static void glnvg__renderViewport(void* uptr, int width, int height, int alphaBlend)
{
struct GLNVGcontext* gl = (struct GLNVGcontext*)uptr;
gl->viewWidth = (float)width;
gl->viewHeight = (float)height;
+
+ if (alphaBlend == NVG_PREMULTIPLIED_ALPHA)
+ glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA, GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
+ else
+ glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
}
-static void glnvg__renderFlush(void* uptr)
+
+static void glnvg__renderFlush(void* uptr, int alphaBlend)
{
// struct GLNVGcontext* gl = (struct GLNVGcontext*)uptr;
NVG_NOTUSED(uptr);
+ NVG_NOTUSED(alphaBlend);
}
static int glnvg__maxVertCount(const struct NVGpath* paths, int npaths)
View
9 src/nanovg_gl3.h
@@ -632,14 +632,19 @@ static int glnvg__setupPaint(struct GLNVGcontext* gl, struct NVGpaint* paint, st
return 1;
}
-static void glnvg__renderViewport(void* uptr, int width, int height)
+static void glnvg__renderViewport(void* uptr, int width, int height, int alphaBlend)
{
struct GLNVGcontext* gl = (struct GLNVGcontext*)uptr;
gl->viewWidth = (float)width;
gl->viewHeight = (float)height;
+
+ if (alphaBlend == NVG_PREMULTIPLIED_ALPHA)
+ glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA, GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
+ else
+ glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
}
-static void glnvg__renderFlush(void* uptr)
+static void glnvg__renderFlush(void* uptr, int alphaBlend)
{
// struct GLNVGcontext* gl = (struct GLNVGcontext*)uptr;
NVG_NOTUSED(uptr);
View
9 src/nanovg_gl3buf.h
@@ -636,9 +636,10 @@ static void glnvg__setUniforms(struct GLNVGcontext* gl, int uniformOffset, int i
}
}
-static void glnvg__renderViewport(void* uptr, int width, int height)
+static void glnvg__renderViewport(void* uptr, int width, int height, int alphaBlend)
{
struct GLNVGcontext* gl = (struct GLNVGcontext*)uptr;
+ NVG_NOTUSED(alphaBlend);
gl->view[0] = (float)width;
gl->view[1] = (float)height;
}
@@ -727,7 +728,7 @@ static void glnvg__triangles(struct GLNVGcontext* gl, struct GLNVGcall* call)
glDrawArrays(GL_TRIANGLES, call->triangleOffset, call->triangleCount);
}
-static void glnvg__renderFlush(void* uptr)
+static void glnvg__renderFlush(void* uptr, int alphaBlend)
{
struct GLNVGcontext* gl = (struct GLNVGcontext*)uptr;
int i;
@@ -736,6 +737,10 @@ static void glnvg__renderFlush(void* uptr)
glUseProgram(gl->shader.prog);
glEnable(GL_CULL_FACE);
+ if (alphaBlend == NVG_PREMULTIPLIED_ALPHA)
+ glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA, GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
+ else
+ glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
// Upload ubo for frag shaders
glBindBuffer(GL_UNIFORM_BUFFER, gl->fragBuf);

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