WIP fragment shader demo

1 files changed, 53 insertions, 16 deletions

diff --git a/main.c b/main.c
index ab5f97b..8ac0ca2 100644
--- a/main.c
+++ b/main.c
@@ -1,40 +1,77 @@
 #include <stdlib.h>
+#include <GL/glew.h>
 #include <GLFW/glfw3.h>
 
-#include "draw.h"
+#include "shader.h"
 #include "die.h"
 
-void resize_handler(GLFWwindow* window, int width, int height) {
-	glViewport(0, 0, width, height);
+#include "hello_vert.h"
+#include "hello_frag.h"
+
+void prepare_tri(GLuint* VBO, GLuint* VAO) {
+	const float vertices[] = {
+		-0.5f, -0.5f, 0.0f,
+		0.5f, -0.5f, 0.0f,
+		0.0f,  0.5f, 0.0f,
+	};
+
+	// initialize vertex {buffer,attribute} object buffers
+	glGenBuffers(1, VBO);
+	glBindBuffer(GL_ARRAY_BUFFER, *VBO);
+	glGenBuffers(1, VAO);
+	glBindVertexArray(*VAO);
+
+	// copy vertex data into VBO
+	glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
+
+	// set VAO pointers
+	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);
+	glEnableVertexAttribArray(0);
 }
 
 int main(int argc, char** argv) {
 	glfwInit();
-
 	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
 	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
-
 	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
 
-	int width = 800, height = 600;
-	GLFWwindow* window = glfwCreateWindow(width, height, "vis", NULL, NULL);
+	// force floating window w/ i3
+	glfwWindowHint(GLFW_FLOATING, GL_TRUE);
+	glfwWindowHint(GLFW_RESIZABLE, GLFW_FALSE);
 
-	if (window == NULL) {
-		glfwTerminate();
+	// initialize window
+	GLFWwindow* window = glfwCreateWindow(800, 600, "vis", NULL, NULL);
+	if (window == NULL)
 		die("error: could not create window\n");
-	}
-
 	glfwMakeContextCurrent(window);
-	glfwSetFramebufferSizeCallback(window, resize_handler);
-	resize_handler(window, width, height);
 
+	// initialize GLEW
+	glewInit();
+
+	// create single triangle
+	GLuint VBO, VAO;
+	prepare_tri(&VBO, &VAO);
+
+	// prepare shaders
+	GLuint shader = link_shaders(
+		vert_shader(hello_vert, hello_vert_size),
+		frag_shader(hello_frag, hello_frag_size)
+	);
+
+	// main draw loop
 	while (!glfwWindowShouldClose(window)) {
-		draw(window);
-		glfwSwapBuffers(window);
 		glfwPollEvents();
+
+		glClearColor(1.f, 0.f, 1.f, 1.0f);
+		glClear(GL_COLOR_BUFFER_BIT);
+
+		glUseProgram(shader);
+		glBindVertexArray(VAO);
+		glDrawArrays(GL_TRIANGLES, 0, 3);
+
+		glfwSwapBuffers(window);
 	}
 
-	glfwTerminate();
 	return EXIT_SUCCESS;
 }