wip framebuffers

shaders/frag.glsl

@@ -4,8 +4,7 @@ uniform float iTime;
 uniform vec2 iResolution;
 uniform sampler2D frame0;
 in vec2 vUV;
-out vec4 fragColor;
-layout(location = 0) out vec4 fragColor2;
+layout(location = 0) out vec4 fragColor;
 
 void main() {
     vec2 uv0 = vUV.st;
@@ -14,5 +13,4 @@ void main() {
     vec3 color = vec3(vUV, sin(iTime * 0.5) * 0.5 + 0.5);
     color *= 1 - step(cos(iTime) * 0.1 + 0.5,length(uv1));
     fragColor = vec4(color, 1.0);
-    fragColor2 = vec4(color, 1.0);
 }

src/constants.h

@@ -4,7 +4,7 @@
 #define CONSTANTS_H
 
 static char *vertex_shader_text =
-    "#version 330\n"
+    "#version 460\n"
     "uniform mat4 mvp;\n"
     "in vec2 vPos;\n"
     "out vec2 vUV;\n"
@@ -14,6 +14,16 @@ static char *vertex_shader_text =
     "    vUV = vPos;\n"
     "}\n";
 
+static char *output_fragment_shader_text =
+    "#version 460\n"
+    "in vec2 vUV;\n"
+    "out vec4 fragColor;\n"
+    "uniform sampler2D frame0\n"
+    "void main()\n"
+    "{\n"
+    "    fragColor = vec4(texture(frame0, vUV).xyz, 1.0);\n"
+    "}\n";
+
 static const Vertex vertices[6] = {{{0.0f, 0.0f}}, {{0.0f, 1.0f}},
                                    {{1.0f, 1.0f}}, {{0.0f, 0.0f}},
                                    {{1.0f, 1.0f}}, {{1.0f, 0.0f}}};

src/shaders.c

@@ -103,6 +103,11 @@ ShaderProgram init_program(File fragment_shader, Context context) {
   program.error |= !compile_shader(
       program.fragment_shader, fragment_shader.path, fragment_shader.content);
 
+  program.output_fragment_shader = glCreateShader(GL_FRAGMENT_SHADER);
+  program.error |=
+      !compile_shader(program.output_fragment_shader,
+                      "internal fragment shader", output_fragment_shader_text);
+
   if (program.error) {
     return program;
   }
@@ -111,6 +116,7 @@ ShaderProgram init_program(File fragment_shader, Context context) {
   program.program = glCreateProgram();
   glAttachShader(program.program, program.vertex_shader);
   glAttachShader(program.program, program.fragment_shader);
+  glAttachShader(program.program, program.output_fragment_shader);
   glLinkProgram(program.program);
 
   // create uniforms pointers

src/types.h

@@ -34,6 +34,7 @@ typedef struct ShaderProgram {
 
   GLuint vertex_shader;
   GLuint fragment_shader;
+  GLuint output_fragment_shader;
 
   GLuint mvp_location;
   GLuint itime_location;