From 6d1c43c6b726d9a834fedc2d187e5345dab9a3fc Mon Sep 17 00:00:00 2001
From: Moritz Ruge <ruge.moritz@gmail.com>
Date: Thu, 6 Aug 2026 17:51:31 +0200
Subject: triangles exercise 3 - 2 shader

---
 main.c | 23 +++++++++++++++++++++--
 1 file changed, 21 insertions(+), 2 deletions(-)

diff --git a/main.c b/main.c
index c4ef368..c88c88a 100644
--- a/main.c
+++ b/main.c
@@ -18,8 +18,8 @@ int main(void) {
     unsigned int VBO[2], VAO[2], EBO;
     // fragment shader
     unsigned int vertex_shader;
-    unsigned int fragment_shader;
-    unsigned int shader_program;
+    unsigned int fragment_shader, fragment_shader2;
+    unsigned int shader_program, shader_program_2;
 
     char info_Log[512];
     // vertex shader source
@@ -39,6 +39,13 @@ int main(void) {
 	"void main() {\n"
 	    "FragColor = vec4(1.0f, 0.5f, 0.2f, 1.0f);\n"
 	"}\n\0";
+    const char* fragment_shader_source_2 =
+	"#version 460 core\n"
+	"out vec4 FragColor;\n"
+	"\n"
+	"void main() {\n"
+	    "FragColor = vec4(1.0f, 1.0f, 0.0f, 1.0f);\n"
+	"}\n\0";
 
     // Triangle shenanigans and now two of them!
     // -----------------------------------------
@@ -112,11 +119,15 @@ int main(void) {
 
     // fragment_shader
     fragment_shader = glCreateShader(GL_FRAGMENT_SHADER);
+    fragment_shader2 = glCreateShader(GL_FRAGMENT_SHADER);
     glShaderSource(fragment_shader, 1, &fragment_shader_source, NULL);
+    glShaderSource(fragment_shader2, 1, &fragment_shader_source_2, NULL);
     glCompileShader(fragment_shader);
+    glCompileShader(fragment_shader2);
 
     // check for compilation error
     glGetShaderiv(fragment_shader, GL_COMPILE_STATUS, &shader_success);
+    glGetShaderiv(fragment_shader2, GL_COMPILE_STATUS, &shader_success);
     if (!shader_success) {
 	glGetShaderInfoLog(fragment_shader, 512, NULL, info_Log);
 	printf("ERROR SHADER FRAGMENT COMPILATION FAILED: %s\n", info_Log);
@@ -125,11 +136,16 @@ int main(void) {
     // create shader program
     // ---------------------
     shader_program = glCreateProgram();
+    shader_program_2 = glCreateProgram();
     // attach to shader program id
     glAttachShader(shader_program, vertex_shader);
     glAttachShader(shader_program, fragment_shader);
     glLinkProgram(shader_program);
 
+    glAttachShader(shader_program_2, vertex_shader);
+    glAttachShader(shader_program_2, fragment_shader2);
+    glLinkProgram(shader_program_2);
+
     // check for linking erros
     glGetProgramiv(shader_program, GL_LINK_STATUS, &shader_success);
     if (!shader_success) {
@@ -140,6 +156,7 @@ int main(void) {
     // delete now unneeded shaders
     glDeleteShader(vertex_shader);
     glDeleteShader(fragment_shader);
+    glDeleteShader(fragment_shader2);
 
     // set up vertex data (and buffers) and configure vertex attributes
     // ----------------------------------------------------------------
@@ -201,6 +218,7 @@ int main(void) {
 	glBindVertexArray(VAO[0]);
 	glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
 	glDrawArrays(GL_TRIANGLES, 4, 6);
+	glUseProgram(shader_program_2);
 	glBindVertexArray(VAO[1]);
 	glDrawArrays(GL_TRIANGLES, 0, 3);
 
@@ -215,6 +233,7 @@ int main(void) {
     glDeleteBuffers(2, VBO);
     glDeleteBuffers(1, &EBO);
     glDeleteProgram(shader_program);
+    glDeleteProgram(shader_program_2);
 
     // Terminate program
     // -----------------
-- 
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