395 lines
8.7 KiB
C
395 lines
8.7 KiB
C
#include <stdio.h>
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#include <GL/glew.h>
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#include <GLFW/glfw3.h>
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#include "vertexShader.c"
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#include "fragmentShader.c"
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#include <stdlib.h>
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#include <math.h>
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#include <string.h>
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#define RESTART 345678
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typedef struct {
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GLfloat x;
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GLfloat y;
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GLfloat z;
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} Point;
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GLuint program;
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GLuint vao;
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GLuint indicesBufferObject;
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GLfloat aspectRatio = 1.0f;
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GLfloat step = 0.0f;
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Point corners[] = {
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{ 1.0f, 1.0f, 1.0f },
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{ 1.0f, 1.0f, -1.0f },
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{ 1.0f, -1.0f, 1.0f },
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{ 1.0f, -1.0f, -1.0f },
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{ -1.0f, 1.0f, 1.0f },
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{ -1.0f, 1.0f, -1.0f },
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{ -1.0f, -1.0f, 1.0f },
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{ -1.0f, -1.0f, -1.0f }
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};
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GLuint indices[] = {
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0, 1,
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0, 2,
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0, 4,
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1, 3,
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1, 5,
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2, 3,
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2, 6,
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3, 7,
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4, 5,
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4, 6,
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5, 7,
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6, 7
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};
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// CREATE 4x4 IDENTITY MATRIX
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void identity(GLfloat* out) {
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for (int i = 0; i < 16; i++) {
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out[i] = (i % 4 == i / 4);
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}
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}
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// CREATE 4x4 TRANSLATION MATRIX
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void translation(GLfloat* out, GLfloat* v) {
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identity(out);
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for (int i = 0; i < 3; i++) {
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out[3 * 4 + i] = v[i];
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}
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}
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// CREATE 4x4 SCALING MATRIX
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void scaling(GLfloat* out, GLfloat* v) {
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identity(out);
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for (int i = 0; i < 3; i++) {
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out[i * 5] = v[i];
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}
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}
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// CREATE 4x4 ROTATION MATRIX AROUND Z AXIS
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/* cos a -sin a 0 0
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* sin a cos a 0 0
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* 0 0 1 0
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* 0 0 0 1
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*/
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void rotationZ(GLfloat* out, GLfloat angle) {
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identity(out);
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out[0] = cos(angle);
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out[1] = sin(angle);
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out[4] = -sin(angle);
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out[5] = cos(angle);
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}
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// CREATE 4x4 ROTATION MATRIX AROUND Y AXIS
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void rotationY(GLfloat* out, GLfloat angle) {
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identity(out);
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out[0] = cos(angle);
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out[2] = -sin(angle);
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out[8] = sin(angle);
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out[10] = cos(angle);
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}
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// CREATE 4x4 ROTATION MATRIX AROUND Y AXIS
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void rotationX(GLfloat* out, GLfloat angle) {
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identity(out);
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out[5] = cos(angle);
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out[6] = sin(angle);
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out[9] = -sin(angle);
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out[10] = cos(angle);
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}
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// MULTIPLY ANY TO MATRICES
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void multiplyAny(GLfloat* A, GLfloat* B, GLfloat* out, int wA, int hA, int wB) {
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int sizeOut = hA * wB;
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GLfloat* result = (GLfloat*) malloc(sizeOut * sizeof(GLfloat));
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for (int i = 0; i < sizeOut; i++) {
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result[i] = 0;
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// printf("%d: ", i);
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for (int j = 0; j < wA; j++) {
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// printf("%d : %f ", j * hA + i % hA, A[j * hA + i % hA]);
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result[i] += A[j * hA + i % hA] * B[j + i / hA * wB];
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}
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// printf("\n");
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}
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memcpy(out, result, sizeOut * sizeof(GLfloat));
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free(result);
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}
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// MULTIPLY TWO 4x4 MATRICES
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void multiply(GLfloat* A, GLfloat* B, GLfloat* out) {
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multiplyAny(A, B, out, 4, 4, 4);
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}
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// MULTIPLY 4x4 MATRIX WITH VEC4
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void multiplyV(GLfloat* M, GLfloat* v, GLfloat* out) {
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multiplyAny(M, v, out, 4, 4, 1);
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}
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// MULTIPLY in WITH TRANSLATION MATRIX OF v
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void translate(GLfloat* out, GLfloat* in, GLfloat* v) {
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GLfloat translationMatrix[16];
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translation(translationMatrix, v);
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multiply(translationMatrix, in, out);
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}
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// MULTIPLY in WITH SCALING MATRIX OF v
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void scale(GLfloat* out, GLfloat* in, GLfloat* v) {
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GLfloat scalingMatrix[16];
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scaling(scalingMatrix, v);
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multiply(scalingMatrix, in, out);
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}
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// MULTIPLY in WITH ROTATION MATRIX OF a AROUND Z AXIS
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void rotateZ(GLfloat* out, GLfloat* in, GLfloat angle) {
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GLfloat rotationMatrix[16];
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rotationZ(rotationMatrix, angle);
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multiply(rotationMatrix, in, out);
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}
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// MULTIPLY in WITH ROTATION MATRIX OF a AROUND Y AXIS
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void rotateY(GLfloat* out, GLfloat* in, GLfloat angle) {
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GLfloat rotationMatrix[16];
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rotationY(rotationMatrix, angle);
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multiply(rotationMatrix, in, out);
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}
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// MULTIPLY in WITH ROTATION MATRIX OF a AROUND X AXIS
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void rotateX(GLfloat* out, GLfloat* in, GLfloat angle) {
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GLfloat rotationMatrix[16];
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rotationX(rotationMatrix, angle);
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multiply(rotationMatrix, in, out);
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}
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void init(void) {
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// create and compile vertex shader
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GLchar *vertexText = malloc(vertexShader_glsl_len);
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memcpy(vertexText, vertexShader_glsl, vertexShader_glsl_len);
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const GLchar *vertexTextConst = vertexText;
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GLuint vertexShader = glCreateShader(GL_VERTEX_SHADER);
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glShaderSource(vertexShader, 1, &vertexTextConst, &vertexShader_glsl_len);
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glCompileShader(vertexShader);
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GLint status;
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glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &status);
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if (!status) {
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printf("Error compiling vertex shader: ");
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GLchar infoLog[1024];
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glGetShaderInfoLog(vertexShader, 1024, NULL, infoLog);
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printf("%s",infoLog);
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}
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free(vertexText);
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vertexText = NULL;
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vertexTextConst = NULL;
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// create and compile fragment shader
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GLchar *fragmentText = malloc(fragmentShader_glsl_len);
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memcpy(fragmentText, fragmentShader_glsl, fragmentShader_glsl_len);
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const GLchar *fragmentTextConst = fragmentText;
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GLuint fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
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glShaderSource(fragmentShader, 1, &fragmentTextConst, &fragmentShader_glsl_len);
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glCompileShader(fragmentShader);
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glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &status);
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if (!status) {
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printf("Error compiling fragment shader: ");
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GLchar infoLog[1024];
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glGetShaderInfoLog(fragmentShader, 1024, NULL, infoLog);
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printf("%s",infoLog);
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}
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free(fragmentText);
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fragmentText = NULL;
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fragmentTextConst = NULL;
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// create and link shader program
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program = glCreateProgram();
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glAttachShader(program, vertexShader);
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glAttachShader(program, fragmentShader);
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glLinkProgram(program);
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glGetProgramiv(program, GL_LINK_STATUS, &status);
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if (!status) {
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printf("Error linking program: ");
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GLchar infoLog[1024];
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glGetProgramInfoLog(program, 1024, NULL, infoLog);
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printf("%s",infoLog);
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}
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glValidateProgram(program);
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glGetProgramiv(program, GL_VALIDATE_STATUS, &status);
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if (!status) {
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printf("Error validating program: ");
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GLchar infoLog[1024];
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glGetProgramInfoLog(program, 1024, NULL, infoLog);
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printf("%s",infoLog);
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}
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GLuint triangleVertexBufferObject;
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glGenBuffers(1, &triangleVertexBufferObject);
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glBindBuffer(GL_ARRAY_BUFFER, triangleVertexBufferObject);
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glBufferData(GL_ARRAY_BUFFER, sizeof(corners), corners, GL_STATIC_DRAW);
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glBindBuffer(GL_ARRAY_BUFFER, 0);
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// create vertex array object
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glGenVertexArrays(1, &vao);
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glBindVertexArray(vao);
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glBindBuffer(GL_ARRAY_BUFFER, triangleVertexBufferObject);
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glVertexAttribPointer(
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0,
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3,
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GL_FLOAT,
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GL_FALSE,
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sizeof(Point),
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0
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);
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glEnableVertexAttribArray(0);
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glBindBuffer(GL_ARRAY_BUFFER, 0);
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glBindVertexArray(0);
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// ENABLE BACKFACE CULLING
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glFrontFace(GL_CW);
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glEnable(GL_CULL_FACE);
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glEnable(GL_PRIMITIVE_RESTART);
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glPrimitiveRestartIndex(RESTART);
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// DEFINE INDEX ARRAY FOR ELEMENT DRAWING
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glGenBuffers(1, &indicesBufferObject);
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glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indicesBufferObject);
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glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
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glClearColor(0.1f, 0.1f, 0.1f, 1.0f);
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}
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void draw(void) {
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glClear(GL_COLOR_BUFFER_BIT);
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glUseProgram(program);
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glBindVertexArray(vao);
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glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indicesBufferObject);
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step += 0.001f;
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if (step > 1.0f) step -= 1.0f;
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GLfloat M[16];
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GLfloat scaleFactor = sin(step * 3.14159f * 2) * 0.1f + 0.2f;
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// GLfloat scaleFactor = 0.2f;
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GLfloat scaleBy[3] = {scaleFactor / aspectRatio, scaleFactor, scaleFactor};
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GLfloat translateBy[3] = {sin(step * 3.14159f * 4.0f), 0.0f, 0.0f};
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identity(M);
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rotateY(M, M, step * 3.14159f * 2);
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rotateX(M, M, step * 3.14159f * 2 + 1.0f);
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rotateZ(M, M, step * 3.14159f * 2 + 0.5f);
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scale(M, M, scaleBy);
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// translate(M, M, translateBy);
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glUniformMatrix4fv(glGetUniformLocation(program, "transformation"), 1, GL_FALSE, M);
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glDrawElements(GL_LINES, sizeof(indices) / sizeof(GLuint), GL_UNSIGNED_INT, NULL);
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}
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void framebuffer_size_callback(GLFWwindow *window, int width, int height) {
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glViewport(0, 0, width, height);
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aspectRatio = (float)width / height;
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}
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int main(void) {
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// GLfloat A[16];
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// GLfloat B[16];
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// GLfloat v[] = {1.0f, 2.0f, 3.0f};
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// GLfloat angle = 1.5f;
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// identity(A);
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// identity(B);
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// multiplyAny(A, B, A, 4, 4, 4);
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// translate(A, A, v);
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// scale(A, A, v);
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// rotateZ(A, A, angle);
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// // DEBUG
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// // PRINT COLUMN MAJOR MATRIX
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// for (int i = 0; i < 16; i++) {
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// if (i != 0 && i % 4 == 0) printf("\n");
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// // cursed stuff to print column major form
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// printf("%.2f ", A[i % 4 * 4 + i / 4]);
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// }
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// printf("\n");
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// // ------
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// return 0;
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glfwInit();
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glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
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glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
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glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
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GLFWwindow *window = glfwCreateWindow(600, 600, "Computergrafik 1", NULL, NULL);
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if (!window) {
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printf("Failed to create window\n");
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glfwTerminate();
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return -1;
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}
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glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
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glfwMakeContextCurrent(window);
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glewInit();
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printf("OpenGL version supported by this platform (%s):\n", glGetString(GL_VERSION));
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init();
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while (!glfwWindowShouldClose(window)) {
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draw();
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glfwSwapBuffers(window);
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glfwPollEvents();
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}
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glfwTerminate();
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return 0;
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} |