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proper camera and perspective transform

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This commit is contained in:
Trammell hudson 2018-02-28 21:15:06 -05:00
parent d48ffe52b4
commit 78de86f4a8
Failed to extract signature
1 changed files with 33 additions and 27 deletions
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60
camera.c
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@ -55,29 +55,22 @@ camera_setup(
// and the "up" normal // and the "up" normal
v3_t v = v3_norm(v3_cross(w, u)); v3_t v = v3_norm(v3_cross(w, u));
float cam[4][4] = {}; float cam[4][4] = {
#if 0
{ u.p[0], v.p[0], w.p[0], 0 },
{ u.p[1], v.p[1], w.p[1], 0 },
{ u.p[2], v.p[2], w.p[2], 0 },
{ -v3_dot(u,eye), -v3_dot(v,eye), -v3_dot(w,eye), 1 },
#else
{ u.p[0], u.p[1], u.p[2], -v3_dot(u,lookat) },
{ v.p[0], v.p[1], v.p[2], -v3_dot(v,lookat) },
{ w.p[0], w.p[1], w.p[2], -v3_dot(w,lookat) },
{ 0, 0, 0, 1 },
#endif
};
cam[0][0] = u.p[0];
cam[1][0] = u.p[1];
cam[2][0] = u.p[2];
cam[3][0] = 0;
cam[0][1] = v.p[0];
cam[1][1] = v.p[1];
cam[2][1] = v.p[2];
cam[3][1] = 0;
cam[0][2] = w.p[0];
cam[1][2] = w.p[1];
cam[2][2] = w.p[2];
cam[3][2] = 0;
// compute u dot c, v dot c, w, dot c
cam[0][3] = -v3_dot(lookat, u);
cam[1][3] = -v3_dot(lookat, v);
cam[2][3] = -v3_dot(lookat, w);
cam[3][3] = 1;
fprintf(stderr, "Camera:\n");
for(int i = 0 ; i < 4 ; i++) for(int i = 0 ; i < 4 ; i++)
{ {
for(int j = 0 ; j < 4 ; j++) for(int j = 0 ; j < 4 ; j++)
@ -88,8 +81,8 @@ camera_setup(
// now compute the perspective projection matrix // now compute the perspective projection matrix
float s = 1.0 / tan(fov * M_PI / 180 / 2); float s = 1.0 / tan(fov * M_PI / 180 / 2);
c->near = 1.0; c->near = 1.0;
c->far = 200; c->far = 20;
float f1 = - c->far * (c->far - c->near); float f1 = - c->far / (c->far - c->near);
float f2 = - c->far * c->near / (c->far - c->near); float f2 = - c->far * c->near / (c->far - c->near);
float pers[4][4] = { float pers[4][4] = {
@ -99,6 +92,14 @@ camera_setup(
{ 0, 0, f2, 0 }, { 0, 0, f2, 0 },
}; };
fprintf(stderr, "Perspective:\n");
for(int i = 0 ; i < 4 ; i++)
{
for(int j = 0 ; j < 4 ; j++)
fprintf(stderr, " %+5.3f", pers[i][j]);
fprintf(stderr, "\n");
}
// and apply it to the camera matrix to generate transform // and apply it to the camera matrix to generate transform
for(int i = 0 ; i < 4 ; i++) for(int i = 0 ; i < 4 ; i++)
{ {
@ -106,10 +107,13 @@ camera_setup(
{ {
float d = 0; float d = 0;
for(int k = 0 ; k < 4 ; k++) for(int k = 0 ; k < 4 ; k++)
d += cam[i][k] * pers[k][j]; d += pers[i][k] * cam[k][j];
c->r[i][j] = d; c->r[i][j] = d;
} }
} }
fprintf(stderr, "Cam*Pers\n");
for(int i = 0 ; i < 4 ; i++) for(int i = 0 ; i < 4 ; i++)
{ {
for(int j = 0 ; j < 4 ; j++) for(int j = 0 ; j < 4 ; j++)
@ -136,9 +140,9 @@ camera_project(
for (int i = 0 ; i < 4 ; i++) for (int i = 0 ; i < 4 ; i++)
for (int j = 0 ; j < 4 ; j++) for (int j = 0 ; j < 4 ; j++)
p[i] += c->r[j][i] * v[j]; p[i] += c->r[i][j] * v[j];
if(0) fprintf(stderr, "%.2f,%.2f,%.2f -> %.2f,%.2f,%.2f,%.2f\n", if(1) fprintf(stderr, "%.2f %.2f %.2f -> %.2f %.2f %.2f %.2f\n",
v[0], v[1], v[2], v[0], v[1], v[2],
p[0], p[1], p[2], p[3] p[0], p[1], p[2], p[3]
); );
@ -146,8 +150,10 @@ camera_project(
/* /*
for (int i = 0 ; i < 3 ; i++) for (int i = 0 ; i < 3 ; i++)
p[i] /= p[3]; p[i] /= p[3];
*/ p[0] *= -1;
p[1] *= -1;
p[2] /= p[3]; p[2] /= p[3];
*/
// Transform to screen coordinate frame, // Transform to screen coordinate frame,