From 3d23c46fbdde1fabe2f24a73fe1c3392b3e7906b Mon Sep 17 00:00:00 2001
From: ktyl <me@ktyl.dev>
Date: Mon, 5 Jul 2021 08:51:55 +0100
Subject: [PATCH] fady boi

---
 res/shader/shader.frag |  4 +++-
 res/shader/shader.vert |  3 +++
 src/gfx.c              |  8 ++++++++
 src/gfx.h              |  2 +-
 src/main.c             | 26 ++++++++++++++++++++++----
 5 files changed, 37 insertions(+), 6 deletions(-)

diff --git a/res/shader/shader.frag b/res/shader/shader.frag
index 0c56a32..9218613 100644
--- a/res/shader/shader.frag
+++ b/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;
 }
diff --git a/res/shader/shader.vert b/res/shader/shader.vert
index c74ea10..27b97ea 100644
--- a/res/shader/shader.vert
+++ b/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);
 }
diff --git a/src/gfx.c b/src/gfx.c
index eaad344..1b73a6f 100644
--- a/src/gfx.c
+++ b/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);
diff --git a/src/gfx.h b/src/gfx.h
index 0f08199..6e752f7 100644
--- a/src/gfx.h
+++ b/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();
 
diff --git a/src/main.c b/src/main.c
index 5ebdc77..73599ef 100644
--- a/src/main.c
+++ b/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;