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perspective sizes

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This commit is contained in:
Recep Aslantas
2018-01-04 13:54:35 +03:00
parent d53f95314d
commit 642cc8d603
2 changed files with 40 additions and 1 deletions
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26
include/cglm/cam.h
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@@ -478,6 +478,32 @@ glm_persp_aspect(mat4 proj) {
return proj[1][1] / proj[0][0];
}
/*!
* @brief returns aspect ratio of perspective projection
*
* if you don't have fovy then use glm_persp_fovy(proj) to get it
* or pass directly: glm_persp_sizes(proj, glm_persp_fovy(proj), sizes);
*
* @param[in] proj perspective projection matrix
* @param[in] fovy fovy (see brief)
* @param[out] dest sizes order: [Wnear, Hnear, Wfar, Hfar]
*/
CGLM_INLINE
void
glm_persp_sizes(mat4 proj, float fovy, vec4 dest) {
float t, a, nearVal, farVal;
t = 2.0f * tanf(fovy * 0.5f);
a = glm_persp_aspect(proj);
glm_persp_decomp_z(proj, &nearVal, &farVal);
dest[1] = t * nearVal;
dest[3] = t * farVal;
dest[0] = a * dest[1];
dest[2] = a * dest[3];
}
/*!
* @brief extracts view frustum planes
*

15
test/src/test_cam.c
View File

@@ -9,7 +9,8 @@
void
test_camera_decomp(void **state) {
mat4 proj;
mat4 proj, proj2;
vec4 sizes;
float aspect, fovy, nearVal, farVal;
aspect = 0.782f;
@@ -21,5 +22,17 @@ test_camera_decomp(void **state) {
assert_true(fabsf(aspect - glm_persp_aspect(proj)) < FLT_EPSILON);
assert_true(fabsf(fovy - glm_persp_fovy(proj)) < FLT_EPSILON);
assert_true(fabsf(49.984f - glm_deg(glm_persp_fovy(proj))) < FLT_EPSILON);
glm_persp_sizes(proj, fovy, sizes);
glm_frustum(-sizes[0] * 0.5,
sizes[0] * 0.5,
-sizes[1] * 0.5,
sizes[1] * 0.5,
nearVal,
farVal,
proj2);
test_assert_mat4_eq(proj, proj2);
}