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drawing functions with alpha support
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@AndrewAPrice
AndrewAPrice committed Dec 11, 2014
1 parent d16d283 commit 024099d
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Showing 2 changed files with 128 additions and 16 deletions.
138 changes: 122 additions & 16 deletions kernel/draw.c
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Original file line number Diff line number Diff line change
Expand Up @@ -4,22 +4,29 @@ void draw_sprite_1bit_alpha(size_t x, size_t y, uint32 *sprite, size_t width, si
size_t start_x = x;
size_t start_y = y;

if(minx > start_x)
start_x = minx;

if(miny > start_y)
start_y = miny;

size_t end_x = x + width;
size_t end_y = y + height;

if(end_x >= buffer_width)
end_x = buffer_width;
if(end_x > maxx)
end_x = maxx;

if(end_y >= buffer_height)
end_y = buffer_height;
if(end_y > maxy)
end_y = maxy;

size_t out_indx = buffer_width * start_y + start_x;
size_t in_indx = 0;
size_t in_indx = (start_x - x) + width * (start_y - y);
size_t _x, _y;
for(_y = start_y; _y != end_y; _y++) {

for(_y = start_y; _y < end_y; _y++) {
size_t next_out_indx = out_indx + buffer_width;
size_t next_in_indx = in_indx + width;
for(_x = start_x; _x != end_x; _x++) {
for(_x = start_x; _x < end_x; _x++) {
uint32 clr = sprite[in_indx];
if(clr) /* test for transparency */
buffer[out_indx] = clr;
Expand All @@ -31,27 +38,80 @@ void draw_sprite_1bit_alpha(size_t x, size_t y, uint32 *sprite, size_t width, si
}
}

void draw_sprite_alpha(size_t x, size_t y, uint32 *sprite, size_t width, size_t height,
uint32 *buffer, size_t buffer_width, size_t buffer_height, size_t minx, size_t miny, size_t maxx, size_t maxy) {
size_t start_x = x;
size_t start_y = y;

if(minx > start_x)
start_x = minx;

if(miny > start_y)
start_y = miny;

size_t end_x = x + width;
size_t end_y = y + height;

if(end_x > maxx)
end_x = maxx;

if(end_y > maxy)
end_y = maxy;

size_t out_indx = buffer_width * start_y + start_x;
size_t in_indx = (start_x - x) + width * (start_y - y);
size_t _x, _y;

for(_y = start_y; _y < end_y; _y++) {
size_t next_out_indx = out_indx + buffer_width;
size_t next_in_indx = in_indx + width;
for(_x = start_x; _x < end_x; _x++) {
uint8 *colour_components = (uint8 *)(&sprite[in_indx]);
size_t alpha = colour_components[3] + 1;
size_t inv_alpha = 256 - colour_components[3];
uint8 *sc_buf = (uint8 *)(&buffer[out_indx]);
sc_buf[0] = (uint8)((alpha * colour_components[0] + inv_alpha * sc_buf[0]) >> 8);
sc_buf[1] = (uint8)((alpha * colour_components[1] + inv_alpha * sc_buf[1]) >> 8);
sc_buf[2] = (uint8)((alpha * colour_components[2] + inv_alpha * sc_buf[2]) >> 8);

out_indx++;
in_indx++;
}
out_indx = next_out_indx;
in_indx = next_in_indx;
}
}

void draw_sprite(size_t x, size_t y, uint32 *sprite, size_t width, size_t height,
uint32 *buffer, size_t buffer_width, size_t buffer_height, size_t minx, size_t miny, size_t maxx, size_t maxy) {
size_t start_x = x;
size_t start_y = y;

if(start_x < minx)
start_x = minx;

if(start_y < miny)
start_y = miny;

size_t end_x = x + width;
size_t end_y = y + height;

if(end_x >= buffer_width)
end_x = buffer_width;
if(end_x > maxx)
end_x = maxx;

if(end_y >= buffer_height)
end_y = buffer_height;
if(end_y > maxy)
end_y = maxy;

size_t out_indx = buffer_width * start_y + start_x;
size_t in_indx = 0;
size_t in_indx = (start_x - x) + width * (start_y - y);

size_t _x, _y;
for(_y = start_y; _y != end_y; _y++) {

for(_y = start_y; _y < end_y; _y++) {
size_t next_out_indx = out_indx + buffer_width;
size_t next_in_indx = in_indx + width;
for(_x = start_x; _x != end_x; _x++) {

for(_x = start_x; _x < end_x; _x++) {
uint32 clr = sprite[in_indx];
buffer[out_indx] = clr;
out_indx++;
Expand All @@ -70,13 +130,36 @@ void draw_x_line(size_t x, size_t y, size_t width, uint32 colour,
size_t end_x = x + width;

if(end_x >= buffer_width)
end_x = buffer_width - 1;
end_x = buffer_width;

size_t indx = buffer_width * y + x;
for(;x != end_x;x++, indx++)
buffer[indx] = colour;
}

void draw_x_line_alpha(size_t x, size_t y, size_t width, uint32 colour,
uint32 *buffer, size_t buffer_width, size_t buffer_height) {
if(y >= buffer_height)
return;

size_t end_x = x + width;

if(end_x >= buffer_width)
end_x = buffer_width;

uint8 *colour_components = (uint8 *)&colour;
size_t alpha = colour_components[3] + 1;
size_t inv_alpha = 256 - colour_components[3];

size_t indx = buffer_width * y + x;
for(;x != end_x;x++, indx++) {
uint8 *sc_buf = (uint8 *)(&buffer[indx]);
sc_buf[0] = (uint8)((alpha * colour_components[0] + inv_alpha * sc_buf[0]) >> 8);
sc_buf[1] = (uint8)((alpha * colour_components[1] + inv_alpha * sc_buf[1]) >> 8);
sc_buf[2] = (uint8)((alpha * colour_components[2] + inv_alpha * sc_buf[2]) >> 8);
}
}

void draw_y_line(size_t x, size_t y, size_t height, uint32 colour,
uint32 *buffer, size_t buffer_width, size_t buffer_height) {
if(x >= buffer_width)
Expand All @@ -85,13 +168,36 @@ void draw_y_line(size_t x, size_t y, size_t height, uint32 colour,
size_t end_y = y + height;

if(end_y >= buffer_height)
end_y = buffer_height - 1;
end_y = buffer_height;

size_t indx = buffer_width * y + x;
for(;y != end_y;y++, indx+=buffer_width)
buffer[indx] = colour;
}

void draw_y_line_alpha(size_t x, size_t y, size_t height, uint32 colour,
uint32 *buffer, size_t buffer_width, size_t buffer_height) {
if(x >= buffer_width)
return;

size_t end_y = y + height;

if(end_y >= buffer_height)
end_y = buffer_height;

uint8 *colour_components = (uint8 *)&colour;
size_t alpha = colour_components[3] + 1;
size_t inv_alpha = 256 - colour_components[3];

size_t indx = buffer_width * y + x;
for(;y != end_y;y++, indx+=buffer_width) {
uint8 *sc_buf = (uint8 *)(&buffer[indx]);
sc_buf[0] = (uint8)((alpha * colour_components[0] + inv_alpha * sc_buf[0]) >> 8);
sc_buf[1] = (uint8)((alpha * colour_components[1] + inv_alpha * sc_buf[1]) >> 8);
sc_buf[2] = (uint8)((alpha * colour_components[2] + inv_alpha * sc_buf[2]) >> 8);
}
}

void plot_pixel(size_t x, size_t y, uint32 colour,
uint32 *buffer, size_t buffer_width, size_t buffer_height) {
if(x >= buffer_width || y >= buffer_height)
Expand Down
6 changes: 6 additions & 0 deletions kernel/draw.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -4,12 +4,18 @@
/* draws a sprite onto the screen with alpha */
extern void draw_sprite_1bit_alpha(size_t x, size_t y, uint32 *sprite, size_t width, size_t height,
uint32 *buffer, size_t buffer_width, size_t buffer_height, size_t minx, size_t miny, size_t maxx, size_t maxy);
extern void draw_sprite_alpha(size_t x, size_t y, uint32 *sprite, size_t width, size_t height,
uint32 *buffer, size_t buffer_width, size_t buffer_height, size_t minx, size_t miny, size_t maxx, size_t maxy);
extern void draw_sprite(size_t x, size_t y, uint32 *sprite, size_t width, size_t height,
uint32 *buffer, size_t buffer_width, size_t buffer_height, size_t minx, size_t miny, size_t maxx, size_t maxy);
extern void draw_x_line(size_t x, size_t y, size_t width, uint32 colour,
uint32 *buffer, size_t buffer_width, size_t buffer_height);
extern void draw_x_line_alpha(size_t x, size_t y, size_t width, uint32 colour,
uint32 *buffer, size_t buffer_width, size_t buffer_height);
extern void draw_y_line(size_t x, size_t y, size_t height, uint32 colour,
uint32 *buffer, size_t buffer_width, size_t buffer_height);
extern void draw_y_line_alpha(size_t x, size_t y, size_t height, uint32 colour,
uint32 *buffer, size_t buffer_width, size_t buffer_height);
extern void plot_pixel(size_t x, size_t y, uint32 colour,
uint32 *buffer, size_t buffer_width, size_t buffer_height);
extern void fill_rectangle(size_t minx, size_t miny, size_t maxx, size_t maxy, uint32 colour,
Expand Down

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