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