factor out init functions

src/gfx.c

@@ -1,8 +1,22 @@
 #include "gfx.h"
+#include "stb_image.h"
 
 const char* vertShaderPath = "res/shader/shader.vert";
 const char* fragShaderPath = "res/shader/shader.frag";
 
+float vertices[] = {
+    // position             color               uvs
+     1.0f,  1.0f,  0.0f,    1.0f, 0.0f, 0.0f,   1.0f, 1.0f, // top right
+     1.0f, -1.0f,  0.0f,    0.0f, 1.0f, 0.0f,   1.0f, 0.0f, // bottom right
+    -1.0f, -1.0f,  0.0f,    0.0f, 0.0f, 1.0f,   0.0f, 0.0f, // bottom left
+    -1.0f,  1.0f,  0.0f,    1.0f, 1.0f, 0.0f,   0.0f, 1.0f  // top left
+};
+
+unsigned int indices[] = {
+    0, 1, 3,
+    1, 2, 3
+};
+
 SDL_Window* sdlWindow;
 SDL_GLContext* sdlContext;
 
@@ -99,3 +113,65 @@ GLuint compileShader(const char* path, GLenum type)
 
     return shader;
 }
+
+void setVertexAttributes()
+{
+    int stride = 8*sizeof(float);
+
+    // position
+    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, stride, (void*)0);
+    glEnableVertexAttribArray(0);
+    // color
+    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, stride, (void*)(3*sizeof(float)));
+    glEnableVertexAttribArray(1);
+    // uv 
+    glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, stride, (void*)(6*sizeof(float)));
+    glEnableVertexAttribArray(2);
+}
+
+void createTextureFromFile()
+{
+    // create an opengl texture and bind it to the GL_TEXTURE_2D target
+    unsigned int texture;
+    glGenTextures(1, &texture);
+    glBindTexture(GL_TEXTURE_2D, texture);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_REPEAT);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_REPEAT);
+
+    // load image data from file
+    const char* imagePath = "res/tex.png";
+    int width, height, nrChannels;
+    stbi_set_flip_vertically_on_load(1);
+    unsigned char* data = stbi_load(imagePath, &width, &height, &nrChannels, 0);
+    if (!data)
+    {
+        fputs("failed to load texture data: ", stderr);
+        fputs(imagePath, stderr);
+        fputs("\n", stderr);
+        exit(1);
+    }
+
+    // read image data into bound opengl texture
+    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);
+    glGenerateMipmap(GL_TEXTURE_2D);
+
+    stbi_image_free(data);
+}
+
+void initBuffers()
+{
+    unsigned int VAO, VBO, EBO;
+    glGenVertexArrays(1, &VAO); // vertex array object
+    glGenBuffers(1, &VBO);      // vertex buffer object
+    glGenBuffers(1, &EBO);      // element buffer object
+
+    glBindVertexArray(VAO);
+
+    glBindBuffer(GL_ARRAY_BUFFER, VBO);
+    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
+
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
+    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
+}

src/gfx.h

@@ -13,3 +13,7 @@ SDL_Window* gfxInit();
 
 unsigned int compileShaderProgram();
 
+void createTextureFromFile();
+void setVertexAttributes();
+void initBuffers();
+

src/main.c

@@ -1,20 +1,6 @@
 #include "main.h"
 
 #include "gfx.h"
-#include "stb_image.h"
-
-float vertices[] = {
-    // position             color               uvs
-     1.0f,  1.0f,  0.0f,    1.0f, 0.0f, 0.0f,   1.0f, 1.0f, // top right
-     1.0f, -1.0f,  0.0f,    0.0f, 1.0f, 0.0f,   1.0f, 0.0f, // bottom right
-    -1.0f, -1.0f,  0.0f,    0.0f, 0.0f, 1.0f,   0.0f, 0.0f, // bottom left
-    -1.0f,  1.0f,  0.0f,    1.0f, 1.0f, 0.0f,   0.0f, 1.0f  // top left
-};
-
-unsigned int indices[] = {
-    0, 1, 3,
-    1, 2, 3
-};
 
 // forward declarations
 
@@ -28,68 +14,13 @@ int main()
 {
     SDL_Window* window = gfxInit();
 
-    // generate opengl texture
+    createTextureFromFile();
-    unsigned int texture;
-    glGenTextures(1, &texture);
-    glBindTexture(GL_TEXTURE_2D, texture);
-    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
-    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
-    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
-    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 
-    // load image data from file
+    initBuffers();
-    const char* imageFile = "res/tex.png";
-    int width, height, nrChannels;
-    stbi_set_flip_vertically_on_load(1);
-    unsigned char* data = stbi_load(imageFile, &width, &height, &nrChannels, 0);
-    if (!data)
-    {
-        fputs("failed to load texture data: ", stderr);
-        fputs(imageFile, stderr);
-        fputs("\n", stderr);
-        exit(1);
-    }
-    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);
-    glGenerateMipmap(GL_TEXTURE_2D);
 
-    // free loaded image data
+    setVertexAttributes();
-    stbi_image_free(data);
 
     unsigned int shaderProgram = compileShaderProgram();
-
-    // vertex array object
-    unsigned int VAO;
-    glGenVertexArrays(1, &VAO);
-    // vertex buffer object
-    unsigned int VBO;                                                   
-    glGenBuffers(1, &VBO);
-    // element buffer object
-    unsigned int EBO;
-    glGenBuffers(1, &EBO);
-
-    glBindVertexArray(VAO);
-
-    // copy our vertices into a buffer opengl can use
-    glBindBuffer(GL_ARRAY_BUFFER, VBO);                                         // bind it to the GL_ARRAY_BUFFER target
-    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);  // copy user-defined data into currently bound buffer
-
-    // copy indices into a buffer for opengl
-    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
-    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
-
-    // set vertex attributes
-
-    int stride = 8*sizeof(float);
-    // position attribute
-    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, stride, (void*)0); // TODO: wtf
-    glEnableVertexAttribArray(0);
-    // color attribute
-    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, stride, (void*)(3 * sizeof(float)));
-    glEnableVertexAttribArray(1);
-    // uv attribute
-    glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, stride, (void*)(6 * sizeof(float)));
-    glEnableVertexAttribArray(2);
-
     glUseProgram(shaderProgram);
 
     // render loop
@@ -99,12 +30,6 @@ int main()
         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);