tonitch/gmath.h
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Camera and vector operations

Browse Source 
I should refactor a bit but it's okay for now
The big improvmeent is lookAt();
This commit is contained in:
Debucquoy Anthony 2023-06-03 11:34:10 +02:00
parent 37c8886662
commit 1cec284de9
1 changed files with 59 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

61
gmath.h
View File

@ -13,6 +13,8 @@ typedef struct {
short height;
} Matrix;
typedef float vec3[3];
typedef enum { GMatrix_Rotation_X, GMatrix_Rotation_Y, GMatrix_Rotation_Z} GMatrix_Rotation;
Matrix GMatrix_malloc(short width, short height);
@ -34,6 +36,12 @@ void GMatrix_vector_scale(Matrix dest, float x, float y, float z);
void GMatrix_vector_translate(Matrix dest, float x, float y, float z);
void GMatrix_vector_rotate(Matrix dest, float d, GMatrix_Rotation r);
float GVector_dist(const vec3 v1, const vec3 v2);
float GVector_lenght(const vec3 v);
void GVector_cross(vec3 dest, const vec3 v1, const vec3 v2);
void GMatrix_view_translate(Matrix dest, float x, float y, float z);
#endif
#ifdef GMATH_IMPLEMENTATION
@ -133,7 +141,7 @@ void GMatrix_vector_scale(Matrix dest, float x, float y, float z){
GMAT_AT(trans, 2, 2) = z;
Matrix ret = {.mat=GMATH_MALLOC(sizeof(float)*dest.width*dest.height), .width=dest.width, .height=dest.height};
GMATH_MEMCPY(ret.mat, dest.mat, sizeof(float)*dest.width*dest.height);
GMatrix_prod(dest, ret, trans);
GMatrix_prod(dest, trans, ret);
free(ret.mat);
}
@ -144,7 +152,7 @@ void GMatrix_vector_translate(Matrix dest, float x, float y, float z){
GMAT_AT(trans, 2, 3) = z;
Matrix ret = {.mat=GMATH_MALLOC(sizeof(float)*dest.width*dest.height), .width=dest.width, .height=dest.height};
GMATH_MEMCPY(ret.mat, dest.mat, sizeof(float)*dest.width*dest.height);
GMatrix_prod(dest, ret, trans);
GMatrix_prod(dest, trans, ret);
free(ret.mat);
}
@ -177,4 +185,53 @@ void GMatrix_vector_rotate(Matrix dest, float d, GMatrix_Rotation r){
free(ret.mat);
}
float GVector_dist(const vec3 v1, const vec3 v2){
return GVector_lenght((vec3) { (v1[0] - v2[0]), (v1[1] - v2[1]), (v1[2] - v2[2]) });
}
float GVector_lenght(const vec3 v){
return sqrtf(powf(v[0], 2) + powf(v[1], 2) + powf(v[2], 2));
}
void GVector_cross(vec3 dest, const vec3 v1, const vec3 v2){
dest[0] = v1[1] * v2[2] - v1[2]*v2[1];
dest[1] = v1[2] * v2[0] - v1[0]*v2[2];
dest[2] = v1[0] * v2[1] - v1[1]*v2[0];
}
void GMatrix_view_lookAt(Matrix dest, vec3 cam_pos, vec3 look_at_pos){
Matrix trans = GMatrix_unit(4);
GMatrix_vector_translate(trans, -cam_pos[0], -cam_pos[1], -cam_pos[2]);
float diff = GVector_dist(cam_pos, look_at_pos);
vec3 forward_vector = {
(cam_pos[0] - look_at_pos[0])/diff,
(cam_pos[1] - look_at_pos[1])/diff,
(cam_pos[2] - look_at_pos[2])/diff
};
vec3 up = { 0., 1., 0. };
vec3 left;
GVector_cross(left, up, forward_vector);
float left_l = GVector_lenght(left);
left[0] = left[0]/left_l;
left[1] = left[1]/left_l;
left[2] = left[2]/left_l;
GVector_cross(up, forward_vector, left);
float rotate_matrix[] = {
left[0], left[1], left[2], 0,
up[0], up[1], up[2], 0,
forward_vector[0], forward_vector[1], forward_vector[2], 0,
0, 0, 0, 1
};
Matrix rotate = {.mat= rotate_matrix, .width=4, .height=4};
Matrix view = GMatrix_unit(4);
GMatrix_prod(view, rotate, trans);
Matrix ret = {.mat=GMATH_MALLOC(sizeof(float)*dest.width*dest.height), .width=dest.width, .height=dest.height};
GMATH_MEMCPY(ret.mat, dest.mat, sizeof(float)*dest.width*dest.height);
GMatrix_prod(dest, ret, view);
free(ret.mat);
}
#endif