csColor GetPixel (float coord_x, float coord_y)
{
// Scale the texture coordinates.
coord_x *= textureScale.x;
coord_y *= textureScale.y;
// Calculate the material coordinates.
float matcoord_x_f = (coord_x * img_w);
float matcoord_y_f = (coord_y * img_h);
int matcoord_x = int (matcoord_x_f);
int matcoord_y = int (matcoord_y_f);
// Bilinearly filter from material.
csColor p00 (GetPixelWrap (img, img_w, img_h,
matcoord_x, matcoord_y));
csColor p01 (GetPixelWrap (img, img_w, img_h,
matcoord_x, matcoord_y+1));
csColor p11 (GetPixelWrap (img, img_w, img_h,
matcoord_x+1, matcoord_y+1));
csColor p10 (GetPixelWrap (img, img_w, img_h,
matcoord_x+1, matcoord_y));
float f1 = matcoord_x_f - matcoord_x;
float f2 = matcoord_y_f - matcoord_y;
return csLerp (csLerp (p00, p10, f1),
csLerp (p01, p11, f1), f2);
}
static csVector3 LerpPC (const csVector3& v1, const csVector3& v2, float t)
{
float iz1 = 1.0f / v1.z;
float iz2 = 1.0f / v2.z;
csVector3 vLerped = csLerp (v1 * iz1, v2 * iz2, t);
float z = 1.0f / csLerp (iz1, iz2, t);
return vLerped * z;
}