Add example of uint texture for testing

1 files changed, 127 insertions, 2 deletions

diff --git a/src/main.c b/src/main.c
index b30280a..0241e8f 100644
--- a/src/main.c
+++ b/src/main.c
@@ -31,8 +31,8 @@ typedef struct Context {
     GLFWwindow *window;
     u32 gl_version_major;
     u32 gl_version_minor;
-    u32 win_width;
-    u32 win_height;
+    s32 win_width;
+    s32 win_height;
     char win_title[256];
     bool win_resizable;
 
@@ -132,6 +132,12 @@ init_context(Context *ctx) {
 }
 
 void
+init_debug_overlay(Context *ctx) {
+    // TODO: Add debug text to context and initialize here
+    (void)ctx;
+}
+
+void
 setup_callbacks(Context *ctx) {
     glfwSetErrorCallback(glfw_error_callback);
     glfwSetKeyCallback(ctx->window, glfw_key_callback);
@@ -167,12 +173,130 @@ update(Context *ctx) {
 
 void
 render(Context *ctx) {
+    glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+    glfwGetFramebufferSize(ctx->window, &ctx->win_width, &ctx->win_height);
+    glViewport(0, 0, ctx->win_width, ctx->win_height);
+
+
+    // TODO: Only need to be done once on the initialization function.
+    // Prepare quad rendering.
+    f32 vertices[] = {
+        // position    // tex_coords
+         1.0f,  1.0f,  1.0f, 1.0f,
+         1.0f, -1.0f,  1.0f, 0.0f,
+        -1.0f, -1.0f,  0.0f, 0.0f,
+        -1.0f,  1.0f,  0.0f, 1.0f,
+    };
+    GLuint indices[] = {
+        0, 1, 3,
+        1, 2, 3
+    };
+
+    // Vertex array object.
+    u32 vao;
+    glGenVertexArrays(1, &vao);
+    glBindVertexArray(vao);
+
+    // Vertex buffer object setup.
+    u32 vbo;
+    glGenBuffers(1, &vbo);
+    glBindBuffer(GL_ARRAY_BUFFER, vbo);
+    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
+    glEnableVertexAttribArray(0);
+    glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(f32), (void*)0);
+    glEnableVertexAttribArray(1);
+    glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(f32), (void*)(2 * sizeof(f32)));
+
+    // Element buffer object setup.
+    u32 ebo;
+    glGenBuffers(1, &ebo);
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ebo);
+    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
+
+    // Texture atlas.
+    u8 texture[] = {
+       0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11,
+       0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11,
+       0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11,
+       0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11,
+       0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11,
+       0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11,
+       0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11,
+       0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11,
+    };
+    u32 tex_id;
+    glGenTextures(1, &tex_id);
+    glBindTexture(GL_TEXTURE_2D, tex_id);
+    glTexImage2D(GL_TEXTURE_2D, 0, GL_R8, 16, 8, 0, GL_RED,
+            GL_UNSIGNED_BYTE, &texture);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+    glBindTexture(GL_TEXTURE_2D, 0);
+
+    // Unbind objects to avoid accidental modifications.
+    glBindVertexArray(0);
+    glBindBuffer(GL_ARRAY_BUFFER, 0);
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
+
+    const char* vert_src =
+"#version 330 core\n"
+"layout (location = 0) in vec2 position;\n"
+"layout (location = 1) in vec2 tex_coords;\n"
+"out vec2 tex;\n"
+"void main() {\n"
+"    gl_Position = vec4(position.x, position.y, 0.0, 1.0);\n"
+"    tex = tex_coords;\n"
+"}";
+
+    // Fragment shader.
+    const char* frag_src =
+"#version 330 core\n"
+"in vec2 tex;\n"
+"out vec4 frag;\n"
+"uniform usampler2D tex_sampler;\n"
+"void main() {\n"
+"    uint val = texture(tex_sampler, tex).r;\n"
+"    frag = vec4(val, val, val, 1.0);\n"
+"}\n";
+
+    u32 program = compile_program(ctx, vert_src, frag_src);
+
+    glUseProgram(program);
+    glBindVertexArray(vao);
+    glBindTexture(GL_TEXTURE_2D, tex_id);
+
+    // TODO: How to pass the parameters for each box?
+    // NOTE: We want to render the text as a single draw call if possible.
+    // glEnable(GL_BLEND);
+    // glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
+    // // glBlendFunc(GL_ONE, GL_ONE);
+    // // glBlendFunc(GL_DST_ALPHA, GL_ONE_MINUS_DST_ALPHA);
+    // // glBlendFunc(GL_SRC_ALPHA, GL_ONE);
+    // // glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+    // // glBlendFunc(GL_ONE, GL_ZERO);
+    // // glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA, GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
+    // // glBlendFunc(GL_DST_ALPHA,GL_ONE);
+    // // glBlendFunc(GL_DST_ALPHA, GL_SRC_ALPHA);
+    // // glBlendFunc(GL_DST_ALPHA, GL_DST_ALPHA);
+    // // glBlendFunc(GL_DST_ALPHA, GL_ONE_MINUS_DST_ALPHA);
+    // // glBlendEquation(GL_FUNC_ADD);
+    //
+    // glBindTexture(GL_TEXTURE_2D, text_tex); // TODO: Bind the texture atlas.
+    glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
+    // glDisable(GL_BLEND);
+
     glfwSwapBuffers(ctx->window);
 }
 
 int
 main(void) {
+
+    //
+    // Initialization.
+    //
+
     Context ctx = (Context){
         .gl_version_major = 3,
         .gl_version_minor = 2,
@@ -182,6 +306,7 @@ main(void) {
     };
     init_context(&ctx);
     setup_callbacks(&ctx);
+    init_debug_overlay(&ctx);
 
     //
     // Main loop.