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cglm/include/cglm/project.h

125 lines
3.5 KiB
C

/*
* Copyright (c), Recep Aslantas.
*
* MIT License (MIT), http://opensource.org/licenses/MIT
* Full license can be found in the LICENSE file
*/
#ifndef cglm_project_h
#define cglm_project_h
#include "common.h"
#include "vec3.h"
#include "vec4.h"
#include "mat4.h"
#ifndef CGLM_CLIPSPACE_INCLUDE_ALL
# if CGLM_CONFIG_CLIP_CONTROL & CGLM_CLIP_CONTROL_ZO_BIT
# include "clipspace/project_zo.h"
# elif CGLM_CONFIG_CLIP_CONTROL & CGLM_CLIP_CONTROL_NO_BIT
# include "clipspace/project_no.h"
# endif
#else
# include "clipspace/project_zo.h"
# include "clipspace/project_no.h"
#endif
/*!
* @brief maps the specified viewport coordinates into specified space [1]
* the matrix should contain projection matrix.
*
* if you don't have ( and don't want to have ) an inverse matrix then use
* glm_unproject version. You may use existing inverse of matrix in somewhere
* else, this is why glm_unprojecti exists to save save inversion cost
*
* [1] space:
* 1- if m = invProj: View Space
* 2- if m = invViewProj: World Space
* 3- if m = invMVP: Object Space
*
* You probably want to map the coordinates into object space
* so use invMVP as m
*
* Computing viewProj:
* glm_mat4_mul(proj, view, viewProj);
* glm_mat4_mul(viewProj, model, MVP);
* glm_mat4_inv(viewProj, invMVP);
*
* @param[in] pos point/position in viewport coordinates
* @param[in] invMat matrix (see brief)
* @param[in] vp viewport as [x, y, width, height]
* @param[out] dest unprojected coordinates
*/
CGLM_INLINE
void
glm_unprojecti(vec3 pos, mat4 invMat, vec4 vp, vec3 dest) {
#if CGLM_CONFIG_CLIP_CONTROL & CGLM_CLIP_CONTROL_ZO_BIT
glm_unprojecti_zo(pos, invMat, vp, dest);
#elif CGLM_CONFIG_CLIP_CONTROL & CGLM_CLIP_CONTROL_NO_BIT
glm_unprojecti_no(pos, invMat, vp, dest);
#endif
}
/*!
* @brief maps the specified viewport coordinates into specified space [1]
* the matrix should contain projection matrix.
*
* this is same as glm_unprojecti except this function get inverse matrix for
* you.
*
* [1] space:
* 1- if m = proj: View Space
* 2- if m = viewProj: World Space
* 3- if m = MVP: Object Space
*
* You probably want to map the coordinates into object space
* so use MVP as m
*
* Computing viewProj and MVP:
* glm_mat4_mul(proj, view, viewProj);
* glm_mat4_mul(viewProj, model, MVP);
*
* @param[in] pos point/position in viewport coordinates
* @param[in] m matrix (see brief)
* @param[in] vp viewport as [x, y, width, height]
* @param[out] dest unprojected coordinates
*/
CGLM_INLINE
void
glm_unproject(vec3 pos, mat4 m, vec4 vp, vec3 dest) {
mat4 inv;
glm_mat4_inv(m, inv);
glm_unprojecti(pos, inv, vp, dest);
}
/*!
* @brief map object coordinates to window coordinates
*
* Computing MVP:
* glm_mat4_mul(proj, view, viewProj);
* glm_mat4_mul(viewProj, model, MVP);
*
* @param[in] pos object coordinates
* @param[in] m MVP matrix
* @param[in] vp viewport as [x, y, width, height]
* @param[out] dest projected coordinates
*/
CGLM_INLINE
void
glm_project(vec3 pos, mat4 m, vec4 vp, vec3 dest) {
CGLM_ALIGN(16) vec4 pos4, vone = GLM_VEC4_ONE_INIT;
glm_vec4(pos, 1.0f, pos4);
glm_mat4_mulv(m, pos4, pos4);
glm_vec4_scale(pos4, 1.0f / pos4[3], pos4); /* pos = pos / pos.w */
glm_vec4_add(pos4, vone, pos4);
glm_vec4_scale(pos4, 0.5f, pos4);
dest[0] = pos4[0] * vp[2] + vp[0];
dest[1] = pos4[1] * vp[3] + vp[1];
dest[2] = pos4[2];
}
#endif /* cglm_project_h */