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117 lines
2.5 KiB
C
117 lines
2.5 KiB
C
/*
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* Copyright (c), Recep Aslantas.
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*
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* MIT License (MIT), http://opensource.org/licenses/MIT
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* Full license can be found in the LICENSE file
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*/
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/*
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TODO: GLdouble vs float ?
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*/
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#ifndef glm_vcam_h
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#define glm_vcam_h
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#include "cglm.h"
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#include <math.h>
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CGLM_INLINE
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void
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glm_frustum(float left,
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float right,
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float bottom,
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float top,
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float near,
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float far,
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mat4 dest) {
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/* https://www.opengl.org/sdk/docs/man2/xhtml/glFrustum.xml */
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glm__memzero(float, dest, sizeof(mat4));
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dest[0][0] = 2.0f * near / (right - left);
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dest[1][1] = 2.0f * near / (top - bottom);
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dest[2][0] = (right + left) / (right - left);
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dest[2][1] = (top + bottom) / (top - bottom);
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dest[2][2] = -(far + near) / (far - near);
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dest[2][3] = -1.0f;
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dest[3][2] = -2.0f * far * near / (far - near);
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}
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CGLM_INLINE
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void
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glm_ortho(float left,
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float right,
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float bottom,
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float top,
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float near,
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float far,
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mat4 dest) {
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/* https://www.opengl.org/sdk/docs/man2/xhtml/glOrtho.xml */
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glm__memzero(float, dest, sizeof(mat4));
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dest[0][0] = 2.0f / (right - left);
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dest[1][1] = 2.0f / (top - bottom);
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dest[2][2] =-2.0f / (far - near);
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dest[3][0] =-(right + left) / (right - left);
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dest[3][1] =-(top + bottom) / (top - bottom);
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dest[3][2] =-(far + near) / (far - near);
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}
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CGLM_INLINE
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void
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glm_perspective(float fovy,
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float aspect,
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float near,
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float far,
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mat4 dest) {
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/* https://www.opengl.org/sdk/docs/man2/xhtml/gluPerspective.xml */
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float f;
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glm__memzero(float, dest, sizeof(mat4));
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f = cosf(fovy * 0.5f) / sinf(fovy * 0.5f);
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dest[0][0] = f / aspect;
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dest[1][1] = f;
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dest[2][2] = (near + far) / (near - far);
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dest[2][3] =-1.0f;
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dest[3][2] = 2 * near * far / (near - far);
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}
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CGLM_INLINE
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void
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glm_lookat(vec3 eye,
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vec3 center,
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vec3 up,
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mat4 dest) {
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vec3 f, u, s;
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glm_vec_sub(center, eye, f);
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glm_vec_normalize(f);
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glm_vec_cross(f, up, s);
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glm_vec_normalize(s);
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glm_vec_cross(s, f, u);
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dest[0][0] = s[0];
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dest[1][0] = s[1];
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dest[2][0] = s[2];
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dest[0][1] = u[0];
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dest[1][1] = u[1];
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dest[2][1] = u[2];
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dest[0][2] =-f[0];
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dest[1][2] =-f[1];
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dest[2][2] =-f[2];
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dest[3][0] =-glm_vec_dot(s, eye);
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dest[3][1] =-glm_vec_dot(u, eye);
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dest[3][2] = glm_vec_dot(f, eye);
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dest[0][3] = 0;
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dest[1][3] = 0;
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dest[2][3] = 0;
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dest[3][3] = 1;
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}
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#endif /* glm_vcam_h */
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