commit 542affc01b82be365dcf7252a659c28bc7094368
parent 819d9623f0256e9b3c8d7aa83829d3339599341e
Author: mjkloeckner <martin.cachari@gmail.com>
Date: Wed, 28 Dec 2022 18:43:05 -0300
draw triangle with shaders
added neccesary code to draw a triangle using shaders
Diffstat:
| M | main.c | | | 105 | +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
| D | opengl | | | 0 | |
2 files changed, 105 insertions(+), 0 deletions(-)
diff --git a/main.c b/main.c
@@ -35,10 +35,115 @@ int main (void) {
glfwMakeContextCurrent(win);
+
if((err = glewInit()) != 0) {
fprintf(stderr, "GLEW: %s\n", glewGetErrorString(err));
return 2;
}
+ /* Vertex Input (or Vertex Data) */
+ float vertices[] = {
+ -0.5f, -0.5f, 0.0f,
+ 0.5f, -0.5f, 0.0f,
+ 0.0f, 0.5f, 0.0f,
+ };
+
+ unsigned int VBO; /* Vertex Buffer Objects */
+ glGenBuffers(1, &VBO); /* Generate an unique ID to VBO */
+ glBindBuffer(GL_ARRAY_BUFFER, VBO); /* bind VBO to a Vertex Buffer type */
+
+
+ /* Copy the previously defined Vertex Data (vertices) into the buffer's
+ * memory.
+ * The fourth parameter specifies how we want the GPU to manage the given
+ * data:
+ * - GL_STREAM_DRAW: the data is set only once and used by the GPU.
+ * - GL_STATIC_DRAW: the data is set only once and used many times.
+ * - GL_DYNAMIC_DRAW: the data is changed a lot and used many times. */
+ glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
+
+ /* Vertex Shader */
+ const char *vertexShaderSource = "#version 410 core\n"
+ "layout (location = 0) in vec3 aPos;\n"
+ "void main() {\n"
+ " gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);\n"
+ "}\0";
+
+ unsigned int vertexShader;
+ vertexShader = glCreateShader(GL_VERTEX_SHADER);
+ glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
+ glCompileShader(vertexShader);
+
+ /* Check if the Vertex Shader compiled succesfully */
+ int success;
+ char infoLog[512];
+ glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
+ if(!success) {
+ glGetShaderInfoLog(vertexShader, 512, NULL, infoLog);
+ fprintf(stderr, "OpenGL: Vertex Shader Compilation failed\n%s\n",
+ infoLog);
+ }
+
+ /* Fragment Shader */
+ const char *fragmentShaderSource = "#version 410 core\n"
+ "out vec4 fragColor;\n"
+ "void main() {\n"
+ "fragColor = vec4(1.0f, 0.0f, 0.0f, 1.0f);\n"
+ "}\n";
+
+ unsigned int fragmentShader;
+ fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
+ glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
+ glCompileShader(fragmentShader);
+
+ /* Check if the Fragment Shader compiled succesfully */
+ glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
+ if(!success) {
+ glGetShaderInfoLog(fragmentShader, 512, NULL, infoLog);
+ fprintf(stderr, "OpenGL: Fragment Shader Compilation failed\n%s\n",
+ infoLog);
+ }
+
+ /* Shader Program */
+ unsigned int shaderProgram;
+ shaderProgram = glCreateProgram();
+
+ glAttachShader(shaderProgram, vertexShader);
+ glAttachShader(shaderProgram, fragmentShader);
+ glLinkProgram(shaderProgram);
+
+ /* Check if linking program failed */
+ glGetProgramiv(shaderProgram, GL_LINK_STATUS, &success);
+ if(!success) {
+ glGetProgramInfoLog(shaderProgram, 512, NULL, infoLog);
+ fprintf(stderr, "OpenGL: Linking Program with Shaders failed\n%s\n",
+ infoLog);
+ }
+
+ /* Free memory */
+ glDeleteShader(vertexShader);
+ glDeleteShader(fragmentShader);
+
+
+ unsigned int VAO;
+ glGenVertexArrays(1, &VAO);
+ glBindVertexArray(VAO);
+
+ /* Linking Vertex attributes */
+ glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE,
+ 3 * sizeof(float), (void *)0);
+ glEnableVertexAttribArray(0);
+ glUseProgram(shaderProgram);
+ glBindVertexArray(VAO);
+
+ while (!glfwWindowShouldClose(win)) {
+ glClear(GL_COLOR_BUFFER_BIT);
+
+ glDrawArrays(GL_TRIANGLES, 0, 3);
+
+ glfwSwapBuffers(win);
+ glfwPollEvents();
+ }
+
return 0;
}
diff --git a/opengl b/opengl
Binary files differ.
