computer-grafik-1/u03-4/main.c

291 lines
6.2 KiB
C

#include <stdio.h>
#include <GL/glew.h>
#include <GLFW/glfw3.h>
#include "vertexShader.c"
#include "fragmentShader.c"
#include <stdlib.h>
#include <math.h>
#include <string.h>
/**
* 0.15 0.25
* | |
*
* 0__1 8__9 ___0.6
* | | | |
* | | | |
* | 4_____6 | ___0.05
* | 5_____7 |
* | | | |
* | | | |
* 2__3 10_11
*
* 12__________14 __-0.75
* 13__________15 __-0.85
*
*/
#define RESTART 345678
typedef struct {
GLfloat x;
GLfloat y;
GLfloat value;
} Point;
GLuint program;
GLuint vao;
GLfloat rotation;
void init(void) {
// create and compile vertex shader
GLchar *vertexText = malloc(vertexShader_glsl_len);
memcpy(vertexText, vertexShader_glsl, vertexShader_glsl_len);
const GLchar *vertexTextConst = vertexText;
GLuint vertexShader = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vertexShader, 1, &vertexTextConst, &vertexShader_glsl_len);
glCompileShader(vertexShader);
GLint status;
glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &status);
if (!status) {
printf("Error compiling vertex shader: ");
GLchar infoLog[1024];
glGetShaderInfoLog(vertexShader, 1024, NULL, infoLog);
printf("%s",infoLog);
}
free(vertexText);
vertexText = NULL;
vertexTextConst = NULL;
// create and compile fragment shader
GLchar *fragmentText = malloc(fragmentShader_glsl_len);
memcpy(fragmentText, fragmentShader_glsl, fragmentShader_glsl_len);
const GLchar *fragmentTextConst = fragmentText;
GLuint fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fragmentShader, 1, &fragmentTextConst, &fragmentShader_glsl_len);
glCompileShader(fragmentShader);
glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &status);
if (!status) {
printf("Error compiling fragment shader: ");
GLchar infoLog[1024];
glGetShaderInfoLog(fragmentShader, 1024, NULL, infoLog);
printf("%s",infoLog);
}
free(fragmentText);
fragmentText = NULL;
fragmentTextConst = NULL;
// create and link shader program
program = glCreateProgram();
glAttachShader(program, vertexShader);
glAttachShader(program, fragmentShader);
glLinkProgram(program);
glGetProgramiv(program, GL_LINK_STATUS, &status);
if (!status) {
printf("Error linking program: ");
GLchar infoLog[1024];
glGetProgramInfoLog(program, 1024, NULL, infoLog);
printf("%s",infoLog);
}
glValidateProgram(program);
glGetProgramiv(program, GL_VALIDATE_STATUS, &status);
if (!status) {
printf("Error validating program: ");
GLchar infoLog[1024];
glGetProgramInfoLog(program, 1024, NULL, infoLog);
printf("%s",infoLog);
}
size_t size = sizeof(Point) * 16;
Point* corners = (Point *) malloc(size);
corners[0].x = -0.25f;
corners[0].y = 0.6f;
corners[0].value = 0.0625f;
corners[1].x = -0.15f;
corners[1].y = 0.6f;
corners[1].value = 0.125f;
corners[2].x = -0.25f;
corners[2].y = -0.6f;
corners[2].value = 0.1875f;
corners[3].x = -0.15f;
corners[3].y = -0.6f;
corners[3].value = 0.25f;
corners[4].x = -0.15f;
corners[4].y = 0.05f;
corners[4].value = 0.3125f;
corners[5].x = -0.15f;
corners[5].y = -0.05f;
corners[5].value = 0.375f;
corners[6].x = 0.15f;
corners[6].y = 0.05f;
corners[6].value = 0.4375f;
corners[7].x = 0.15f;
corners[7].y = -0.05f;
corners[7].value = 0.5f;
corners[8].x = 0.15f;
corners[8].y = 0.6f;
corners[8].value = 0.5625f;
corners[9].x = 0.25f;
corners[9].y = 0.6f;
corners[9].value = 0.625f;
corners[10].x = 0.15f;
corners[10].y = -0.6f;
corners[10].value = 0.6875f;
corners[11].x = 0.25f;
corners[11].y = -0.6f;
corners[11].value = 0.75f;
corners[12].x = -0.25f;
corners[12].y = -0.75f;
corners[12].value = 0.8125f;
corners[13].x = -0.25f;
corners[13].y = -0.85f;
corners[13].value = 0.875f;
corners[14].x = 0.25f;
corners[14].y = -0.75f;
corners[14].value = 0.9375f;
corners[15].x = 0.25f;
corners[15].y = -0.85f;
corners[15].value = 1.0f;
GLuint triangleVertexBufferObject;
glGenBuffers(1, &triangleVertexBufferObject);
glBindBuffer(GL_ARRAY_BUFFER, triangleVertexBufferObject);
glBufferData(GL_ARRAY_BUFFER, size, corners, GL_STATIC_DRAW);
glBindBuffer(GL_ARRAY_BUFFER, 0);
free(corners);
// create vertex array object
glGenVertexArrays(1, &vao);
glBindVertexArray(vao);
glBindBuffer(GL_ARRAY_BUFFER, triangleVertexBufferObject);
glVertexAttribPointer(
0,
2,
GL_FLOAT,
GL_FALSE,
sizeof(Point),
0
);
glEnableVertexAttribArray(0);
glVertexAttribPointer(
1,
1,
GL_FLOAT,
GL_FALSE,
sizeof(Point),
(GLvoid*)(2 * sizeof(GLfloat))
);
glEnableVertexAttribArray(1);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindVertexArray(0);
glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
}
void draw(void) {
glClear(GL_COLOR_BUFFER_BIT);
glUseProgram(program);
glBindVertexArray(vao);
rotation = rotation + 0.01f;
if (rotation > 2 * 3.1415926f) {
rotation = 0;
}
glUniform1f(glGetUniformLocation(program, "rotation"), rotation);
glFrontFace(GL_CW);
glCullFace(GL_BACK);
glEnable(GL_CULL_FACE);
glEnable(GL_PRIMITIVE_RESTART);
glPrimitiveRestartIndex(RESTART);
GLuint indices[] = {0, 1, 2, 3, RESTART, 4, 6, 5, 7, RESTART, 8, 9, 10, 11, RESTART, 12, 14, 13, 15};
glDrawElements(GL_TRIANGLE_STRIP, sizeof(indices) / sizeof(GLuint), GL_UNSIGNED_INT, indices);
}
void framebuffer_size_callback(GLFWwindow *window, int width, int height) {
glViewport(0, 0, width, height);
}
int main(void) {
glfwInit();
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
GLFWwindow *window = glfwCreateWindow(600, 600, "Computergrafik 1", NULL, NULL);
if (!window) {
printf("Failed to create window\n");
glfwTerminate();
return -1;
}
glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
glfwMakeContextCurrent(window);
glewInit();
printf("OpenGL version supported by this platform (%s):\n", glGetString(GL_VERSION));
init();
while (!glfwWindowShouldClose(window)) {
draw();
glfwSwapBuffers(window);
glfwPollEvents();
}
glfwTerminate();
return 0;
}