86 lines
1.6 KiB
C
86 lines
1.6 KiB
C
#pragma once
|
|
|
|
typedef struct vec3 {
|
|
float v[3];
|
|
} vec3;
|
|
|
|
typedef struct vec4 {
|
|
float v[4];
|
|
} vec4;
|
|
|
|
typedef struct mat3 {
|
|
float v[3*3];
|
|
} mat3;
|
|
|
|
typedef struct mat4 {
|
|
float v[4*4];
|
|
} mat4;
|
|
|
|
static inline mat3 matmul3(const mat3 &a, const mat3 &b) {
|
|
mat3 ret = {{0.0}};
|
|
for (int r=0; r<3; r++) {
|
|
for (int c=0; c<3; c++) {
|
|
float v = 0.0;
|
|
for (int k=0; k<3; k++) {
|
|
v += a.v[r*3+k] * b.v[k*3+c];
|
|
}
|
|
ret.v[r*3+c] = v;
|
|
}
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static inline vec3 matvecmul3(const mat3 &a, const vec3 &b) {
|
|
vec3 ret = {{0.0}};
|
|
for (int r=0; r<3; r++) {
|
|
for (int c=0; c<3; c++) {
|
|
ret.v[r] += a.v[r*3+c] * b.v[c];
|
|
}
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static inline mat4 matmul(const mat4 &a, const mat4 &b) {
|
|
mat4 ret = {{0.0}};
|
|
for (int r=0; r<4; r++) {
|
|
for (int c=0; c<4; c++) {
|
|
float v = 0.0;
|
|
for (int k=0; k<4; k++) {
|
|
v += a.v[r*4+k] * b.v[k*4+c];
|
|
}
|
|
ret.v[r*4+c] = v;
|
|
}
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static inline vec4 matvecmul(const mat4 &a, const vec4 &b) {
|
|
vec4 ret = {{0.0}};
|
|
for (int r=0; r<4; r++) {
|
|
for (int c=0; c<4; c++) {
|
|
ret.v[r] += a.v[r*4+c] * b.v[c];
|
|
}
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
// scales the input and output space of a transformation matrix
|
|
// that assumes pixel-center origin.
|
|
static inline mat3 transform_scale_buffer(const mat3 &in, float s) {
|
|
// in_pt = ( transform(out_pt/s + 0.5) - 0.5) * s
|
|
|
|
mat3 transform_out = {{
|
|
1.0f/s, 0.0f, 0.5f,
|
|
0.0f, 1.0f/s, 0.5f,
|
|
0.0f, 0.0f, 1.0f,
|
|
}};
|
|
|
|
mat3 transform_in = {{
|
|
s, 0.0f, -0.5f*s,
|
|
0.0f, s, -0.5f*s,
|
|
0.0f, 0.0f, 1.0f,
|
|
}};
|
|
|
|
return matmul3(transform_in, matmul3(in, transform_out));
|
|
}
|