commit 1343fe48f47d9e13260017ceca0ee5e7cdd9582e
parent 30a165a3e371b3be8856e4f99f0f6735734c7918
Author: mjkloeckner <martin.cachari@gmail.com>
Date: Tue, 3 Jan 2023 18:22:11 -0300
time and movement to triangle, replaced tabs for spaces
Diffstat:
| M | Makefile | | | 2 | +- |
| M | main.c | | | 314 | ++++++++++++++++++++++++++++++++++++++++++------------------------------------- |
| M | main.vert | | | 4 | +++- |
3 files changed, 173 insertions(+), 147 deletions(-)
diff --git a/Makefile b/Makefile
@@ -1,6 +1,6 @@
CC := gcc
CLIBS := `sdl2-config --libs` $(shell pkg-config --libs glfw3 glew)
-CFLAGS := `sdl2-config --cflags` -Wall -Wshadow -pedantic -ansi -std=c99 -O3
+CFLAGS := `sdl2-config --cflags` -Wall -Wshadow -pedantic -ansi -std=c99 -O3 -lm
SRCS := $(wildcard *.c)
OBJS := $(SRCS:.c=.o)
diff --git a/main.c b/main.c
@@ -3,13 +3,20 @@
#include <GLFW/glfw3.h>
#include <stdio.h>
+#include <math.h>
#define WIN_TITLE "OpenGL Test Window"
#define WIN_WIDTH 800
#define WIN_HEIGHT 600
-#define FRAGMENT_SHADER_FILE_NAME "main.frag"
-#define VERTEX_SHADER_FILE_NAME "main.vert"
+#define FRAGMENT_SHADER_FILE_NAME "main.frag"
+#define VERTEX_SHADER_FILE_NAME "main.vert"
+
+double time = 0.0;
+
+float map(float x, float in_min, float in_max, float out_min, float out_max) {
+ return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
+}
void glfwPrintError(int e, const char *s) {
fprintf(stderr, "%s\n", s);
@@ -20,159 +27,176 @@ void framebufferSizeCallback(GLFWwindow* win, int width, int height) {
}
char *loadShaderFromFile(const char *filename) {
- char *buffer;
- long len;
- FILE *f = fopen(filename, "rb");
+ char *buffer;
+ long len;
+ FILE *f = fopen(filename, "rb");
- if(f) {
- fseek(f, 0, SEEK_END);
- len = ftell(f);
- fseek(f, 0, SEEK_SET);
- buffer = (char *)malloc(len + 1);
- buffer[len] = '\0';
+ if(f) {
+ fseek(f, 0, SEEK_END);
+ len = ftell(f);
+ fseek(f, 0, SEEK_SET);
+ buffer = (char *)malloc(len + 1);
+ buffer[len] = '\0';
- if(buffer)
- fread (buffer, 1, len, f);
+ if(buffer)
+ fread (buffer, 1, len, f);
- fclose (f);
- } else return NULL;
+ fclose (f);
+ } else return NULL;
- return buffer;
+ return buffer;
}
int main (void) {
GLenum err;
- GLFWwindow *win;
- unsigned int VBO, VAO; /* Vertex Buffer Objects, Vertex Array Objects */
- char *vertexShaderSource, *fragmentShaderSource;
- unsigned int vertexShader, fragmentShader, shaderProgram;
- int success;
- char infoLog[512];
-
- if(!glfwInit()) {
- fprintf(stderr, "GLFW: failed to initialize\n");
- return 1;
- }
-
- if(!(win = glfwCreateWindow(WIN_WIDTH, WIN_HEIGHT, WIN_TITLE, NULL, NULL)))
- glfwTerminate();
-
- glfwSetErrorCallback(&glfwPrintError);
- glfwSetFramebufferSizeCallback(win, framebufferSizeCallback);
- glfwMakeContextCurrent(win);
-
- if((err = glewInit())) {
+ GLFWwindow *win;
+ unsigned int VBO, VAO; /* Vertex Buffer Objects, Vertex Array Objects */
+ char *vertexShaderSource, *fragmentShaderSource;
+ unsigned int vertexShader, fragmentShader, shaderProgram;
+ int success;
+ char infoLog[512];
+
+ if(!glfwInit()) {
+ fprintf(stderr, "GLFW: failed to initialize\n");
+ return 1;
+ }
+
+ if(!(win = glfwCreateWindow(WIN_WIDTH, WIN_HEIGHT, WIN_TITLE, NULL, NULL)))
+ glfwTerminate();
+
+ glfwSetErrorCallback(&glfwPrintError);
+ glfwSetFramebufferSizeCallback(win, framebufferSizeCallback);
+ glfwMakeContextCurrent(win);
+
+ if((err = glewInit())) {
fprintf(stderr, "GLEW: %s\n", glewGetErrorString(err));
return 2;
}
- /* Vertex Input (or Vertex Data) */
- float vertices[] = {
- -0.5f, -0.5f,
- 0.5f, -0.5f,
- 0.0f, 0.5f,
- };
-
- /* Generate an unique ID to VBO */
- glGenBuffers(1, &VBO);
-
- /* Bind VBO to a Vertex Buffer type */
- glBindBuffer(GL_ARRAY_BUFFER, VBO);
-
- /* 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 */
- if(!(vertexShaderSource = loadShaderFromFile(VERTEX_SHADER_FILE_NAME))) {
- fprintf(stderr, "could not load shader from file \"%s\n\"",
- VERTEX_SHADER_FILE_NAME);
- return 1;
- }
-
- vertexShader = glCreateShader(GL_VERTEX_SHADER);
- glShaderSource(vertexShader, 1, (char const* const*)&vertexShaderSource, NULL);
- glCompileShader(vertexShader);
-
- /* Check if the Vertex Shader compiled succesfully */
- 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 */
- if(!(fragmentShaderSource = loadShaderFromFile(FRAGMENT_SHADER_FILE_NAME))) {
- fprintf(stderr, "could not load shader from file \"%s\n\"",
- FRAGMENT_SHADER_FILE_NAME);
- return 1;
- }
-
- fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
- glShaderSource(fragmentShader, 1, (char const* const*)&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 */
- 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);
-
- glGenVertexArrays(1, &VAO);
- glBindVertexArray(VAO);
-
- /* Linking Vertex attributes */
- glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE,
- 2 * sizeof(float), (void *)0);
-
- glEnableVertexAttribArray(0);
- glUseProgram(shaderProgram);
- glBindVertexArray(VAO);
-
- /* main loop */
- while (!glfwWindowShouldClose(win)) {
- glClear(GL_COLOR_BUFFER_BIT);
-
- glDrawArrays(GL_TRIANGLES, 0, 3);
-
- glfwSwapBuffers(win);
- glfwPollEvents();
- }
-
- free(vertexShaderSource);
- free(fragmentShaderSource);
-
- glDeleteVertexArrays(1, &VAO);
- glDeleteBuffers(1, &VBO);
- glDeleteProgram(shaderProgram);
-
- glfwDestroyWindow(win);
- glfwTerminate();
- return 0;
+ /* Vertex Input (or Vertex Data) */
+ float vertices[] = {
+ -1.0f, -1.0f,
+ 1.0f, -1.0f,
+ 0.0f, 1.0f,
+ };
+
+ /* Generate an unique ID to VBO */
+ glGenBuffers(1, &VBO);
+
+ /* Bind VBO to a Vertex Buffer type */
+ glBindBuffer(GL_ARRAY_BUFFER, VBO);
+
+ /* 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 */
+ if(!(vertexShaderSource = loadShaderFromFile(VERTEX_SHADER_FILE_NAME))) {
+ fprintf(stderr, "could not load shader from file \"%s\n\"",
+ VERTEX_SHADER_FILE_NAME);
+ return 1;
+ }
+
+ vertexShader = glCreateShader(GL_VERTEX_SHADER);
+ glShaderSource(vertexShader, 1, (char const* const*)&vertexShaderSource, NULL);
+ glCompileShader(vertexShader);
+
+ /* Check if the Vertex Shader compiled succesfully */
+ 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 */
+ if(!(fragmentShaderSource = loadShaderFromFile(FRAGMENT_SHADER_FILE_NAME))) {
+ fprintf(stderr, "could not load shader from file \"%s\n\"",
+ FRAGMENT_SHADER_FILE_NAME);
+ return 1;
+ }
+
+ fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
+ glShaderSource(fragmentShader, 1, (char const* const*)&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 */
+ 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);
+ }
+
+unsigned int gScaleLocation = glGetUniformLocation(shaderProgram, "scale");
+
+ /* Free memory */
+ free(vertexShaderSource);
+ free(fragmentShaderSource);
+ glDeleteShader(vertexShader);
+ glDeleteShader(fragmentShader);
+
+ glGenVertexArrays(1, &VAO);
+ glBindVertexArray(VAO);
+
+ /* Linking Vertex attributes */
+ glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE,
+ 2 * sizeof(float), (void *)0);
+
+ glEnableVertexAttribArray(0);
+ glUseProgram(shaderProgram);
+ glBindVertexArray(VAO);
+
+ /* main loop */
+ time = glfwGetTime();
+ double prev_time = 0.0;
+ double delta_time = 0.0f;
+
+ static float ds = 0.0025f;
+ static float scale = 0.5f;
+ while (!glfwWindowShouldClose(win)) {
+ glClear(GL_COLOR_BUFFER_BIT);
+
+ scale += ds;
+ if((scale >= 0.75f) || (scale <= 0.5f))
+ ds *= -1.0f;
+
+ glUniform1f(gScaleLocation, scale);
+
+ glDrawArrays(GL_TRIANGLES, 0, 3);
+ glfwSwapBuffers(win);
+ glfwPollEvents();
+
+ double cur_time = glfwGetTime();
+ delta_time = cur_time - prev_time;
+ time += delta_time;
+ prev_time = cur_time;
+ }
+
+ glDeleteVertexArrays(1, &VAO);
+ glDeleteBuffers(1, &VBO);
+ glDeleteProgram(shaderProgram);
+
+ glfwDestroyWindow(win);
+ glfwTerminate();
+ return 0;
}
diff --git a/main.vert b/main.vert
@@ -1,6 +1,8 @@
#version 330 core
layout (location = 0) in vec2 pos;
+uniform float scale;
+
void main() {
- gl_Position = vec4(pos.x, pos.y, 0.0, 1.0);
+ gl_Position = vec4(scale * pos.x, scale * pos.y, 0.0, 1.0);
}
