1 // Copyright (c) 2011 The Native Client 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.
5 #include "transforms.h"
11 namespace transform_4x4 {
13 static const GLfloat kPI = 3.1415926535897932384626433832795f;
15 void Translate(GLfloat* m, GLfloat tx, GLfloat ty, GLfloat tz) {
16 m[12] += (m[0] * tx + m[4] * ty + m[8] * tz);
17 m[13] += (m[1] * tx + m[5] * ty + m[9] * tz);
18 m[14] += (m[2] * tx + m[6] * ty + m[10] * tz);
19 m[15] += (m[3] * tx + m[7] * ty + m[11] * tz);
22 void Frustum(GLfloat* m,
29 GLfloat delta_x = right - left;
30 GLfloat delta_y = top - bottom;
31 GLfloat delta_z = far_z - near_z;
34 if ((near_z <= 0.0f) || (far_z <= 0.0f) ||
35 (delta_x <= 0.0f) || (delta_y <= 0.0f) || (delta_z <= 0.0f))
38 frustum[0] = 2.0f * near_z / delta_x;
39 frustum[1] = frustum[2] = frustum[3] = 0.0f;
41 frustum[5] = 2.0f * near_z / delta_y;
42 frustum[4] = frustum[6] = frustum[7] = 0.0f;
44 frustum[8] = (right + left) / delta_x;
45 frustum[9] = (top + bottom) / delta_y;
46 frustum[10] = -(near_z + far_z) / delta_z;
49 frustum[14] = -2.0f * near_z * far_z / delta_z;
50 frustum[12] = frustum[13] = frustum[15] = 0.0f;
52 transform_4x4::Multiply(m, frustum, m);
56 void Perspective(GLfloat* m,
61 GLfloat frustum_w, frustum_h;
63 frustum_h = tanf((fovy * 0.5f) / 180.0f * kPI) * near_z;
64 frustum_w = frustum_h * aspect;
65 transform_4x4::Frustum(m, -frustum_w, frustum_w, -frustum_h, frustum_h,
69 void Multiply(GLfloat *m, GLfloat *a, GLfloat* b) {
72 GLfloat a0, a1, a2, a3;
77 tmp[0] = a0 * b[0] + a1 * b[4] + a2 * b[8] + a3 * b[12];
78 tmp[1] = a0 * b[1] + a1 * b[5] + a2 * b[9] + a3 * b[13];
79 tmp[2] = a0 * b[2] + a1 * b[6] + a2 * b[10] + a3 * b[14];
80 tmp[3] = a0 * b[3] + a1 * b[7] + a2 * b[11] + a3 * b[15];
86 tmp[4] = a0 * b[0] + a1 * b[4] + a2 * b[8] + a3 * b[12];
87 tmp[5] = a0 * b[1] + a1 * b[5] + a2 * b[9] + a3 * b[13];
88 tmp[6] = a0 * b[2] + a1 * b[6] + a2 * b[10] + a3 * b[14];
89 tmp[7] = a0 * b[3] + a1 * b[7] + a2 * b[11] + a3 * b[15];
95 tmp[8] = a0 * b[0] + a1 * b[4] + a2 * b[8] + a3 * b[12];
96 tmp[9] = a0 * b[1] + a1 * b[5] + a2 * b[9] + a3 * b[13];
97 tmp[10] = a0 * b[2] + a1 * b[6] + a2 * b[10] + a3 * b[14];
98 tmp[11] = a0 * b[3] + a1 * b[7] + a2 * b[11] + a3 * b[15];
104 tmp[12] = a0 * b[0] + a1 * b[4] + a2 * b[8] + a3 * b[12];
105 tmp[13] = a0 * b[1] + a1 * b[5] + a2 * b[9] + a3 * b[13];
106 tmp[14] = a0 * b[2] + a1 * b[6] + a2 * b[10] + a3 * b[14];
107 tmp[15] = a0 * b[3] + a1 * b[7] + a2 * b[11] + a3 * b[15];
108 memcpy(m, tmp, sizeof(GLfloat) * 4 * 4);
111 void LoadIdentity(GLfloat* m) {
112 memset(m, 0, sizeof(GLfloat) * 4 * 4);
113 m[0] = m[5] = m[10] = m[15] = 1.0f;
116 } // namespace transform_4x4