fady boi

res/shader/shader.frag

@@ -1,7 +1,9 @@
 #version 330 core
 out vec4 FragColor;
 
+uniform vec4 ourColor;
+
 void main()
 {
-    FragColor = vec4(1.0f, 0.5f, 0.2f, 1.0f);
+    FragColor = ourColor;
 }

res/shader/shader.vert

@@ -1,7 +1,10 @@
 #version 330 core
 layout (location = 0) in vec3 aPos;
 
+out vec4 vertexColor;
+
 void main()
 {
     gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);
+    vertexColor = vec4(0.5, 0.0, 0.0, 1.0);
 }

src/gfx.c

@@ -37,6 +37,12 @@ void gfxInit()
 
     glewExperimental = GL_TRUE;
     glewInit();
+
+    // intiliased opengl
+
+    int availableAttributes;
+    glGetIntegerv(GL_MAX_VERTEX_ATTRIBS, &availableAttributes);
+    //printf("max vertex attributes %d\n", availableAttributes);
 }
 
 unsigned int compileShaderProgram()
@@ -47,6 +53,8 @@ unsigned int compileShaderProgram()
     unsigned int shaderProgram = glCreateProgram();
     glAttachShader(shaderProgram, vs);
     glAttachShader(shaderProgram, fs);
+
+    // TODO: check program linking success
     glLinkProgram(shaderProgram);
 
     glDeleteShader(vs);

src/gfx.h

@@ -3,6 +3,7 @@
 #define GLEW_STATIC
 #include "GL/glew.h"
 
+
 #include <SDL2/SDL.h>
 #include <SDL2/SDL_opengl.h>
 
@@ -11,7 +12,6 @@
 void gfxInit();
 SDL_Window* getWindow();
 SDL_GLContext* getContext();
-GLuint compileShader(const char* path, GLenum type);
 
 unsigned int compileShaderProgram();
 

src/main.c

@@ -15,8 +15,13 @@ unsigned int indices[] = {
 };
 
 // forward declarations
+
+// input
 int checkQuit();
 
+// time
+float time();
+
 int main()
 {
     gfxInit();
@@ -24,8 +29,6 @@ int main()
 
     unsigned int shaderProgram = compileShaderProgram();
 
-    // TODO: check program linking success
-
     // vertex array object
     unsigned int VAO;
     glGenVertexArrays(1, &VAO);
@@ -50,19 +53,34 @@ int main()
     glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3*sizeof(float), (void*)0); // TODO: wtf
     glEnableVertexAttribArray(0);
 
+    glUseProgram(shaderProgram);
+
     // render loop
     while (!checkQuit())
     {
-        glUseProgram(shaderProgram);
+        // clear background
+        glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
+        glClear(GL_COLOR_BUFFER_BIT);
 
+        // update uniforms
+        float time = (float)SDL_GetTicks() / 1000.0f;
+        float greenValue = (sin(time)/2.0f)+0.5f;
+        int vertexColorLocation = glGetUniformLocation(shaderProgram, "ourColor");
+        glUniform4f(vertexColorLocation, 0.0f, greenValue, 0.0f, 1.0f);
+
+        // draw
         glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
-
         SDL_GL_SwapWindow(window);
     }
 
     return 0;
 }
 
+float time()
+{
+    return (float)SDL_GetTicks() / 1000.0f; // ms / 1000.0 = seconds since start
+}
+
 int checkQuit()
 {
     SDL_Event event;