Created
March 16, 2015 09:51
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| void mmul(float* m, const float* a, const float* b) | |
| { | |
| for (int r = 0; r < 4; r++) | |
| for (int c = 0; c < 4; c++) | |
| m[r*4+c] = a[r*4+0] * b[0*4+c] + a[r*4+1] * b[1*4+c] + a[r*4+2] * b[2*4+c] + a[r*4+3] * b[3*4+c]; | |
| } | |
| void midentity(float* m) | |
| { | |
| for (int i = 0; i < 4; i++) | |
| for (int j = 0; j < 4; j++) | |
| m[i*4+j] = i == j ? 1 : 0; | |
| } | |
| void minverse(float* inv, const float* src) | |
| { | |
| int i, j, k; | |
| float t; | |
| float temp[4][4]; | |
| for (i = 0; i < 4; i++) | |
| for (j = 0; j <4; j++) | |
| temp[i][j] = src[i*4+j]; | |
| midentity(inv); | |
| for (i = 0; i < 4; i++) | |
| { | |
| if (temp[i][i] == 0.0f) | |
| { | |
| for (j = i + 1; j < 4; j++) | |
| if (temp[j][i] != 0.0f) | |
| break; | |
| if (j != 4) | |
| { | |
| for (k = 0; k < 4; k++) | |
| { | |
| t = temp[i][k]; | |
| temp[i][k] = temp[j][k]; | |
| temp[j][k] = t; | |
| t = inv[i*4+k]; | |
| inv[i*4+k] = inv[j*4+k]; | |
| inv[j*4+k] = t; | |
| } | |
| } | |
| else | |
| { | |
| return; | |
| } | |
| } | |
| t = 1.0f / temp[i][i]; | |
| for (k = 0; k < 4; k++) | |
| { | |
| temp[i][k] *= t; | |
| inv[i*4+k] *= t; | |
| } | |
| for (j = 0; j < 4; j++) | |
| { | |
| if (j != i) | |
| { | |
| t = temp[j][i]; | |
| for (k = 0; k < 4; k++) | |
| { | |
| temp[j][k] -= temp[i][k]*t; | |
| inv[j*4+k] -= inv[i*4+k]*t; | |
| } | |
| } | |
| } | |
| } | |
| } | |
| inline void transpoint4(float* r, const float* m, const float* v) | |
| { | |
| r[0] = v[0]*m[0] + v[1]*m[4] + v[2]*m[8] + v[3]*m[12]; | |
| r[1] = v[0]*m[1] + v[1]*m[5] + v[2]*m[9] + v[3]*m[13]; | |
| r[2] = v[0]*m[2] + v[1]*m[6] + v[2]*m[10] + v[3]*m[14]; | |
| r[3] = v[0]*m[3] + v[1]*m[7] + v[2]*m[11] + v[3]*m[15]; | |
| } | |
| void project(float x, float y, float z, const float* model, const float* proj, | |
| int w, int h, float* pos) | |
| { | |
| float A[16]; | |
| float in[4], out[4]; | |
| in[0]=x; in[1]=y; in[2]=z; in[3]=1; | |
| mmul(A, model, proj); | |
| transpoint4(out, A, in); | |
| pos[0] = ((out[0]/out[3])+1)*w/2; | |
| pos[1] = ((out[1]/out[3])+1)*h/2; | |
| pos[2] = (out[2]/out[3]); | |
| } | |
| void unproject(float wx, float wy, float wz, | |
| const float* model, const float* proj, | |
| int w, int h, float* pos) | |
| { | |
| float m[16], A[16]; | |
| float in[4], out[4]; | |
| in[0] = (wx/w)*2 - 1; | |
| in[1] = (wy/h)*2 - 1; | |
| in[2] = wz*2 - 1; | |
| in[3] = 1; | |
| mmul(A, model, proj); | |
| minverse(m, A); | |
| transpoint4(out, m, in); | |
| if (out[3] == 0.0f) | |
| return; | |
| pos[0] = out[0] / out[3]; | |
| pos[1] = out[1] / out[3]; | |
| pos[2] = out[2] / out[3]; | |
| } |
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