simplify code

src/shaders.c

@@ -152,7 +152,6 @@ static void init_single_program(ShaderProgram *program, unsigned int i,
   } else {
     glAttachShader(program->programs[i], program->fragment_shaders[i]);
   }
-
   glLinkProgram(program->programs[i]);
 
   // create uniforms pointers
@@ -276,10 +275,8 @@ void shaders_update(ShaderProgram program, File *fragment_shaders,
   }
 }
 
-void shaders_apply(ShaderProgram program, Context context) {
-  unsigned int i, j;
-  GLuint subroutines[3];
-  vec2 resolution;
+static void update_viewport(ShaderProgram program, Context context) {
+  unsigned int i;
 
   // viewport changed
   if (context.width != program.last_width ||
@@ -294,15 +291,21 @@ void shaders_apply(ShaderProgram program, Context context) {
                    GL_RGB, GL_UNSIGNED_BYTE, 0);
     }
   }
+}
+
+static void use_program(ShaderProgram program, int i, bool output,
+                        Context context) {
+  unsigned int j;
+  GLuint subroutines[3];
+  vec2 resolution;
 
   resolution[0] = (float)context.width;
   resolution[1] = (float)context.height;
 
-  for (i = 0; i < program.frag_count + 1; i++) {
   // use specific shader program
   glUseProgram(program.programs[i]);
 
-    if (i == program.frag_count) {
+  if (output) {
     // use default framebuffer (output)
     glBindFramebuffer(GL_FRAMEBUFFER, 0);
 
@@ -337,4 +340,13 @@ void shaders_apply(ShaderProgram program, Context context) {
   // draw output
   glDrawArrays(GL_TRIANGLES, 0, 6);
 }
+
+void shaders_apply(ShaderProgram program, Context context) {
+  unsigned int i;
+
+  update_viewport(program, context);
+
+  for (i = 0; i < program.frag_count + 1; i++) {
+    use_program(program, i, i == program.frag_count, context);
+  }
 }