Fix debug & refactor shader. 3018 bytes

Makefile

@@ -10,7 +10,7 @@ CFLAGS = -Os -Winline -Wall -Wextra \
 ifeq ($(DEBUG),false)
 	CFLAGS += #-nostdlib # needed for rand()
 else
-	CFLAGS += -DDEBUG=true -g
+	CFLAGS += -DDEBUG_GL=true -g
 	LDFLAGS += -g
 endif
 

Minecraft4k.c

@@ -66,6 +66,18 @@ glUniform3f_t sym_glUniform3f;
 glUniform3i_t sym_glUniform3i;
 glRecti_t sym_glRecti;
 
+#ifdef DEBUG_GL
+typedef void(*glGetShaderInfoLog_t)(GLuint, GLsizei, GLsizei*, GLchar*);
+typedef void(*glGetProgramInfoLog_t)(GLuint, GLsizei, GLsizei*, GLchar*);
+typedef void(*glGetProgramiv_t)(GLuint, GLenum, GLint*);
+typedef void(*glGetShaderiv_t)(GLuint, GLenum, GLint*);
+
+glGetShaderInfoLog_t sym_glGetShaderInfoLog;
+glGetProgramInfoLog_t sym_glGetProgramInfoLog;
+glGetProgramiv_t sym_glGetProgramiv;
+glGetShaderiv_t sym_glGetShaderiv;
+#endif
+
 // OpenGL IDs
 GLuint shader;
 GLuint worldTex;
@@ -516,11 +528,11 @@ static void on_realize()
 
 #ifdef DEBUG_GL
     GLint isCompiled = 0;
-    glGetShaderiv(f, GL_COMPILE_STATUS, &isCompiled);
+    sym_glGetShaderiv(f, GL_COMPILE_STATUS, &isCompiled);
     if(isCompiled == GL_FALSE) {
         const int maxLength = 1024;
         GLchar* error[maxLength];
-        glGetShaderInfoLog(f, maxLength, &maxLength, error);
+        sym_glGetShaderInfoLog(f, maxLength, &maxLength, error);
         printf("%s\n", error);
 
         exit(-10);
@@ -534,11 +546,11 @@ static void on_realize()
 
 #ifdef DEBUG_GL
     GLint isLinked = 0;
-    glGetProgramiv(shader, GL_LINK_STATUS, (int *)&isLinked);
+    sym_glGetProgramiv(shader, GL_LINK_STATUS, (int *)&isLinked);
     if (isLinked == GL_FALSE) {
         const int maxLength = 1024;
         GLchar* error[maxLength]; 
-        glGetProgramInfoLog(shader, maxLength, &maxLength,error);
+        sym_glGetProgramInfoLog(shader, maxLength, &maxLength,error);
         printf("%s\n", error);
 
         exit(-10);
@@ -592,6 +604,13 @@ void _start() {
     sym_glUniform3i = (glUniform3i_t)dlsym(libGL, "glUniform3i");
     sym_glRecti = (glRecti_t)dlsym(libGL, "glRecti");
 
+#ifdef DEBUG_GL
+    sym_glGetShaderInfoLog = (glGetShaderInfoLog_t)dlsym(libGL, "glGetShaderInfoLog");
+    sym_glGetProgramInfoLog = (glGetProgramInfoLog_t)dlsym(libGL, "glGetProgramInfoLog");
+    sym_glGetProgramiv = (glGetProgramiv_t)dlsym(libGL, "glGetProgramiv");
+    sym_glGetShaderiv = (glGetShaderiv_t)dlsym(libGL, "glGetShaderiv");
+#endif
+
     // technically not needed
     //SDL_Init(SDL_INIT_VIDEO | SDL_INIT_EVENTS);
     window = sym_SDL_CreateWindow("", 0, 0,

shader.frag

@@ -38,22 +38,17 @@ void main()
 
     // raymarch outputs
 
-    vec3 ijk = ivec3(P);
-
-    // the amount to increase i, j and k in each axis (either 1 or -1)
-    vec3 ijkStep = sign(rayDir);
-
-    vec3 vInverted = abs(1 / rayDir);
-
-    // the distance to the closest voxel boundary in units of rayTravelDist
-    vec3 dist = (-fract(P) + max(ijkStep, vec3(0))) / rayDir;
-
-    int axis; // X
+    // the distance to the closest voxel boundary in units of rayDir
+    vec3 dist = (-fract(P) + step(vec3(0), rayDir)) / rayDir;
 
     float rayTravelDist;
 
     while (rayTravelDist < 20) // TODO replace RENDER_DIST
     {
+        int axis = (dist.y < dist.x) ? 1 + int(dist.y > dist.z) : 2 * int(dist.x > dist.z);
+        rayTravelDist = dist[axis];
+        dist[axis] += abs(1 / rayDir)[axis];
+
         // exit check for performance, removed for code size :c
         //if(!inWorld(ijk))
         //    break;
@@ -72,37 +67,26 @@ void main()
                 texFetch.y += 2;
         }
 
+        // bit confusing: we repurpose hitPos to fetch the block that was hit
+        hitPos[axis] -= step(0., -rayDir[axis]);
+
         // get block from world
         // TODO replace WORLD_DIMENSIONS
-        texFetch.x += texture(W, ijk.yxz / 64).x * 0xFF;
+        texFetch.x += texture(W, hitPos.yxz / 64).x * 0xFF;
 
         // TODO replace TEXTURE_RES
         vec4 textureColor = texture(T, (trunc(texFetch * 16) + .5) / vec2(112, 48));
 
         // highlight hovered block
         // multiply by 9 to make sure it's white
-        textureColor += int(ijk == b && max(abs(fract(texFetch) - .5).x, abs(fract(texFetch) - .5).y) > .44) * 9;
+        textureColor += int(ivec3(hitPos) == b && max(abs(fract(texFetch) - .5).x, abs(fract(texFetch) - .5).y) > .44) * 9;
 
         if (textureColor.a > 0) { // pixel is not transparent, so output color
 
             // TODO replace RENDER_DIST
             Z += mix(textureColor, vec4(0), rayTravelDist / 20);
             return;
         }
-
-        // determine the closest voxel boundary
-        axis = (dist.y < dist.x) ? 1 + int(dist.y > dist.z) : 2 * int(dist.x > dist.z);
-
-        // advance to the closest voxel boundary in the axis direction
-
-        // increment the block access position
-        ijk[axis] += ijkStep[axis];
-
-        // update our progress in the ray 
-        rayTravelDist = dist[axis];
-
-        // set the new distance to the next voxel Y boundary
-        dist[axis] += vInverted[axis];
     }
 
     //Z = vec4(0);