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Diffstat (limited to 'include/cglm/frustum.h')
| -rw-r--r-- | include/cglm/frustum.h | 255 |
1 files changed, 255 insertions, 0 deletions
diff --git a/include/cglm/frustum.h b/include/cglm/frustum.h new file mode 100644 index 0000000..5aa3c17 --- /dev/null +++ b/include/cglm/frustum.h @@ -0,0 +1,255 @@ +/* + * Copyright (c), Recep Aslantas. + * + * MIT License (MIT), http://opensource.org/licenses/MIT + * Full license can be found in the LICENSE file + */ + +#ifndef cglm_frustum_h +#define cglm_frustum_h + +#include "common.h" +#include "plane.h" +#include "vec3.h" +#include "vec4.h" +#include "mat4.h" + +#define GLM_LBN 0 /* left bottom near */ +#define GLM_LTN 1 /* left top near */ +#define GLM_RTN 2 /* right top near */ +#define GLM_RBN 3 /* right bottom near */ + +#define GLM_LBF 4 /* left bottom far */ +#define GLM_LTF 5 /* left top far */ +#define GLM_RTF 6 /* right top far */ +#define GLM_RBF 7 /* right bottom far */ + +#define GLM_LEFT 0 +#define GLM_RIGHT 1 +#define GLM_BOTTOM 2 +#define GLM_TOP 3 +#define GLM_NEAR 4 +#define GLM_FAR 5 + +/* you can override clip space coords + but you have to provide all with same name + e.g.: define GLM_CSCOORD_LBN {0.0f, 0.0f, 1.0f, 1.0f} */ +#ifndef GLM_CUSTOM_CLIPSPACE + +/* near */ +#define GLM_CSCOORD_LBN {-1.0f, -1.0f, -1.0f, 1.0f} +#define GLM_CSCOORD_LTN {-1.0f, 1.0f, -1.0f, 1.0f} +#define GLM_CSCOORD_RTN { 1.0f, 1.0f, -1.0f, 1.0f} +#define GLM_CSCOORD_RBN { 1.0f, -1.0f, -1.0f, 1.0f} + +/* far */ +#define GLM_CSCOORD_LBF {-1.0f, -1.0f, 1.0f, 1.0f} +#define GLM_CSCOORD_LTF {-1.0f, 1.0f, 1.0f, 1.0f} +#define GLM_CSCOORD_RTF { 1.0f, 1.0f, 1.0f, 1.0f} +#define GLM_CSCOORD_RBF { 1.0f, -1.0f, 1.0f, 1.0f} + +#endif + +/*! + * @brief extracts view frustum planes + * + * planes' space: + * 1- if m = proj: View Space + * 2- if m = viewProj: World Space + * 3- if m = MVP: Object Space + * + * You probably want to extract planes in world space so use viewProj as m + * Computing viewProj: + * glm_mat4_mul(proj, view, viewProj); + * + * Exracted planes order: [left, right, bottom, top, near, far] + * + * @param[in] m matrix (see brief) + * @param[out] dest extracted view frustum planes (see brief) + */ +CGLM_INLINE +void +glm_frustum_planes(mat4 m, vec4 dest[6]) { + mat4 t; + + glm_mat4_transpose_to(m, t); + + glm_vec4_add(t[3], t[0], dest[0]); /* left */ + glm_vec4_sub(t[3], t[0], dest[1]); /* right */ + glm_vec4_add(t[3], t[1], dest[2]); /* bottom */ + glm_vec4_sub(t[3], t[1], dest[3]); /* top */ + glm_vec4_add(t[3], t[2], dest[4]); /* near */ + glm_vec4_sub(t[3], t[2], dest[5]); /* far */ + + glm_plane_normalize(dest[0]); + glm_plane_normalize(dest[1]); + glm_plane_normalize(dest[2]); + glm_plane_normalize(dest[3]); + glm_plane_normalize(dest[4]); + glm_plane_normalize(dest[5]); +} + +/*! + * @brief extracts view frustum corners using clip-space coordinates + * + * corners' space: + * 1- if m = invViewProj: World Space + * 2- if m = invMVP: Object Space + * + * You probably want to extract corners in world space so use invViewProj + * Computing invViewProj: + * glm_mat4_mul(proj, view, viewProj); + * ... + * glm_mat4_inv(viewProj, invViewProj); + * + * if you have a near coord at i index, you can get it's far coord by i + 4 + * + * Find center coordinates: + * for (j = 0; j < 4; j++) { + * glm_vec3_center(corners[i], corners[i + 4], centerCorners[i]); + * } + * + * @param[in] invMat matrix (see brief) + * @param[out] dest exracted view frustum corners (see brief) + */ +CGLM_INLINE +void +glm_frustum_corners(mat4 invMat, vec4 dest[8]) { + vec4 c[8]; + + /* indexOf(nearCoord) = indexOf(farCoord) + 4 */ + vec4 csCoords[8] = { + GLM_CSCOORD_LBN, + GLM_CSCOORD_LTN, + GLM_CSCOORD_RTN, + GLM_CSCOORD_RBN, + + GLM_CSCOORD_LBF, + GLM_CSCOORD_LTF, + GLM_CSCOORD_RTF, + GLM_CSCOORD_RBF + }; + + glm_mat4_mulv(invMat, csCoords[0], c[0]); + glm_mat4_mulv(invMat, csCoords[1], c[1]); + glm_mat4_mulv(invMat, csCoords[2], c[2]); + glm_mat4_mulv(invMat, csCoords[3], c[3]); + glm_mat4_mulv(invMat, csCoords[4], c[4]); + glm_mat4_mulv(invMat, csCoords[5], c[5]); + glm_mat4_mulv(invMat, csCoords[6], c[6]); + glm_mat4_mulv(invMat, csCoords[7], c[7]); + + glm_vec4_scale(c[0], 1.0f / c[0][3], dest[0]); + glm_vec4_scale(c[1], 1.0f / c[1][3], dest[1]); + glm_vec4_scale(c[2], 1.0f / c[2][3], dest[2]); + glm_vec4_scale(c[3], 1.0f / c[3][3], dest[3]); + glm_vec4_scale(c[4], 1.0f / c[4][3], dest[4]); + glm_vec4_scale(c[5], 1.0f / c[5][3], dest[5]); + glm_vec4_scale(c[6], 1.0f / c[6][3], dest[6]); + glm_vec4_scale(c[7], 1.0f / c[7][3], dest[7]); +} + +/*! + * @brief finds center of view frustum + * + * @param[in] corners view frustum corners + * @param[out] dest view frustum center + */ +CGLM_INLINE +void +glm_frustum_center(vec4 corners[8], vec4 dest) { + vec4 center; + + glm_vec4_copy(corners[0], center); + + glm_vec4_add(corners[1], center, center); + glm_vec4_add(corners[2], center, center); + glm_vec4_add(corners[3], center, center); + glm_vec4_add(corners[4], center, center); + glm_vec4_add(corners[5], center, center); + glm_vec4_add(corners[6], center, center); + glm_vec4_add(corners[7], center, center); + + glm_vec4_scale(center, 0.125f, dest); +} + +/*! + * @brief finds bounding box of frustum relative to given matrix e.g. view mat + * + * @param[in] corners view frustum corners + * @param[in] m matrix to convert existing conners + * @param[out] box bounding box as array [min, max] + */ +CGLM_INLINE +void +glm_frustum_box(vec4 corners[8], mat4 m, vec3 box[2]) { + vec4 v; + vec3 min, max; + int i; + + glm_vec3_broadcast(FLT_MAX, min); + glm_vec3_broadcast(-FLT_MAX, max); + + for (i = 0; i < 8; i++) { + glm_mat4_mulv(m, corners[i], v); + + min[0] = glm_min(min[0], v[0]); + min[1] = glm_min(min[1], v[1]); + min[2] = glm_min(min[2], v[2]); + + max[0] = glm_max(max[0], v[0]); + max[1] = glm_max(max[1], v[1]); + max[2] = glm_max(max[2], v[2]); + } + + glm_vec3_copy(min, box[0]); + glm_vec3_copy(max, box[1]); +} + +/*! + * @brief finds planes corners which is between near and far planes (parallel) + * + * this will be helpful if you want to split a frustum e.g. CSM/PSSM. This will + * find planes' corners but you will need to one more plane. + * Actually you have it, it is near, far or created previously with this func ;) + * + * @param[in] corners view frustum corners + * @param[in] splitDist split distance + * @param[in] farDist far distance (zFar) + * @param[out] planeCorners plane corners [LB, LT, RT, RB] + */ +CGLM_INLINE +void +glm_frustum_corners_at(vec4 corners[8], + float splitDist, + float farDist, + vec4 planeCorners[4]) { + vec4 corner; + float dist, sc; + + /* because distance and scale is same for all */ + dist = glm_vec3_distance(corners[GLM_RTF], corners[GLM_RTN]); + sc = dist * (splitDist / farDist); + + /* left bottom */ + glm_vec4_sub(corners[GLM_LBF], corners[GLM_LBN], corner); + glm_vec4_scale_as(corner, sc, corner); + glm_vec4_add(corners[GLM_LBN], corner, planeCorners[0]); + + /* left top */ + glm_vec4_sub(corners[GLM_LTF], corners[GLM_LTN], corner); + glm_vec4_scale_as(corner, sc, corner); + glm_vec4_add(corners[GLM_LTN], corner, planeCorners[1]); + + /* right top */ + glm_vec4_sub(corners[GLM_RTF], corners[GLM_RTN], corner); + glm_vec4_scale_as(corner, sc, corner); + glm_vec4_add(corners[GLM_RTN], corner, planeCorners[2]); + + /* right bottom */ + glm_vec4_sub(corners[GLM_RBF], corners[GLM_RBN], corner); + glm_vec4_scale_as(corner, sc, corner); + glm_vec4_add(corners[GLM_RBN], corner, planeCorners[3]); +} + +#endif /* cglm_frustum_h */ |