1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 /** @file matrix.cc 6 * Implements simple matrix manipulation functions. 7 */ 8 9 //----------------------------------------------------------------------------- 10 #include <stdlib.h> 11 #include <string.h> 12 #include "matrix.h" 13 #define deg_to_rad(x) (x * (M_PI / 180.0f)) 14 15 void glhFrustumf2(Matrix_t mat, 16 GLfloat left, 17 GLfloat right, 18 GLfloat bottom, 19 GLfloat top, 20 GLfloat znear, 21 GLfloat zfar) { 22 float temp, temp2, temp3, temp4; 23 temp = 2.0f * znear; 24 temp2 = right - left; 25 temp3 = top - bottom; 26 temp4 = zfar - znear; 27 mat[0] = temp / temp2; 28 mat[1] = 0.0f; 29 mat[2] = 0.0f; 30 mat[3] = 0.0f; 31 mat[4] = 0.0f; 32 mat[5] = temp / temp3; 33 mat[6] = 0.0f; 34 mat[7] = 0.0f; 35 mat[8] = (right + left) / temp2; 36 mat[9] = (top + bottom) / temp3; 37 mat[10] = (-zfar - znear) / temp4; 38 mat[11] = -1.0f; 39 mat[12] = 0.0f; 40 mat[13] = 0.0f; 41 mat[14] = (-temp * zfar) / temp4; 42 mat[15] = 0.0f; 43 } 44 45 void glhPerspectivef2(Matrix_t mat, 46 GLfloat fovyInDegrees, 47 GLfloat aspectRatio, 48 GLfloat znear, 49 GLfloat zfar) { 50 float ymax, xmax; 51 ymax = znear * tanf(fovyInDegrees * 3.14f / 360.0f); 52 xmax = ymax * aspectRatio; 53 glhFrustumf2(mat, -xmax, xmax, -ymax, ymax, znear, zfar); 54 } 55 56 void identity_matrix(Matrix_t mat) { 57 memset(mat, 0, sizeof(Matrix_t)); 58 mat[0] = 1.0; 59 mat[5] = 1.0; 60 mat[10] = 1.0; 61 mat[15] = 1.0; 62 } 63 64 void multiply_matrix(const Matrix_t a, const Matrix_t b, Matrix_t mat) { 65 // Generate to a temporary first in case the output matrix and input 66 // matrix are the same. 67 Matrix_t out; 68 69 out[0] = a[0] * b[0] + a[4] * b[1] + a[8] * b[2] + a[12] * b[3]; 70 out[1] = a[1] * b[0] + a[5] * b[1] + a[9] * b[2] + a[13] * b[3]; 71 out[2] = a[2] * b[0] + a[6] * b[1] + a[10] * b[2] + a[14] * b[3]; 72 out[3] = a[3] * b[0] + a[7] * b[1] + a[11] * b[2] + a[15] * b[3]; 73 74 out[4] = a[0] * b[4] + a[4] * b[5] + a[8] * b[6] + a[12] * b[7]; 75 out[5] = a[1] * b[4] + a[5] * b[5] + a[9] * b[6] + a[13] * b[7]; 76 out[6] = a[2] * b[4] + a[6] * b[5] + a[10] * b[6] + a[14] * b[7]; 77 out[7] = a[3] * b[4] + a[7] * b[5] + a[11] * b[6] + a[15] * b[7]; 78 79 out[8] = a[0] * b[8] + a[4] * b[9] + a[8] * b[10] + a[12] * b[11]; 80 out[9] = a[1] * b[8] + a[5] * b[9] + a[9] * b[10] + a[13] * b[11]; 81 out[10] = a[2] * b[8] + a[6] * b[9] + a[10] * b[10] + a[14] * b[11]; 82 out[11] = a[3] * b[8] + a[7] * b[9] + a[11] * b[10] + a[15] * b[11]; 83 84 out[12] = a[0] * b[12] + a[4] * b[13] + a[8] * b[14] + a[12] * b[15]; 85 out[13] = a[1] * b[12] + a[5] * b[13] + a[9] * b[14] + a[13] * b[15]; 86 out[14] = a[2] * b[12] + a[6] * b[13] + a[10] * b[14] + a[14] * b[15]; 87 out[15] = a[3] * b[12] + a[7] * b[13] + a[11] * b[14] + a[15] * b[15]; 88 89 memcpy(mat, out, sizeof(Matrix_t)); 90 } 91 92 void rotate_x_matrix(GLfloat x_rad, Matrix_t mat) { 93 identity_matrix(mat); 94 mat[5] = cosf(x_rad); 95 mat[6] = -sinf(x_rad); 96 mat[9] = -mat[6]; 97 mat[10] = mat[5]; 98 } 99 100 void rotate_y_matrix(GLfloat y_rad, Matrix_t mat) { 101 identity_matrix(mat); 102 mat[0] = cosf(y_rad); 103 mat[2] = sinf(y_rad); 104 mat[8] = -mat[2]; 105 mat[10] = mat[0]; 106 } 107 108 void rotate_z_matrix(GLfloat z_rad, Matrix_t mat) { 109 identity_matrix(mat); 110 mat[0] = cosf(z_rad); 111 mat[1] = sinf(z_rad); 112 mat[4] = -mat[1]; 113 mat[5] = mat[0]; 114 } 115 116 void rotate_matrix(GLfloat x_deg, GLfloat y_deg, GLfloat z_deg, Matrix_t mat) { 117 GLfloat x_rad = (GLfloat) deg_to_rad(x_deg); 118 GLfloat y_rad = (GLfloat) deg_to_rad(y_deg); 119 GLfloat z_rad = (GLfloat) deg_to_rad(z_deg); 120 121 Matrix_t x_matrix; 122 Matrix_t y_matrix; 123 Matrix_t z_matrix; 124 125 rotate_x_matrix(x_rad, x_matrix); 126 rotate_y_matrix(y_rad, y_matrix); 127 rotate_z_matrix(z_rad, z_matrix); 128 129 Matrix_t xy_matrix; 130 multiply_matrix(y_matrix, x_matrix, xy_matrix); 131 multiply_matrix(z_matrix, xy_matrix, mat); 132 } 133 134 void translate_matrix(GLfloat x, GLfloat y, GLfloat z, Matrix_t mat) { 135 identity_matrix(mat); 136 mat[12] += x; 137 mat[13] += y; 138 mat[14] += z; 139 } 140
