+#define LERPSPRITES
+
+#ifdef LERPSPRITES
+void R_ClipSpriteImage (vec3_t origin, vec3_t left, vec3_t up)
+{
+ int i;
+ mspriteframe_t *frame;
+ vec3_t points[4];
+ float fleft, fright, fdown, fup;
+ frame = currentrenderentity->model->sprdata_frames + currentrenderentity->frameblend[0].frame;
+ fleft = frame->left;
+ fdown = frame->down;
+ fright = frame->right;
+ fup = frame->up;
+ for (i = 1;i < 4 && currentrenderentity->frameblend[i].lerp;i++)
+ {
+ frame = currentrenderentity->model->sprdata_frames + currentrenderentity->frameblend[i].frame;
+ fleft = min(fleft , frame->left );
+ fdown = min(fdown , frame->down );
+ fright = max(fright, frame->right);
+ fup = max(fup , frame->up );
+ }
+ // FIXME: reverse these in loader to save time
+ fleft = -fleft;
+ fright = -fright;
+ points[0][0] = origin[0] + fdown * up[0] + fleft * left[0];points[0][1] = origin[1] + fdown * up[1] + fleft * left[1];points[0][2] = origin[2] + fdown * up[2] + fleft * left[2];
+ points[1][0] = origin[0] + fup * up[0] + fleft * left[0];points[1][1] = origin[1] + fup * up[1] + fleft * left[1];points[1][2] = origin[2] + fup * up[2] + fleft * left[2];
+ points[2][0] = origin[0] + fup * up[0] + fright * left[0];points[2][1] = origin[1] + fup * up[1] + fright * left[1];points[2][2] = origin[2] + fup * up[2] + fright * left[2];
+ points[3][0] = origin[0] + fdown * up[0] + fright * left[0];points[3][1] = origin[1] + fdown * up[1] + fright * left[1];points[3][2] = origin[2] + fdown * up[2] + fright * left[2];
+ R_Clip_AddPolygon(&points[0][0], 4, sizeof(float[3]), false, R_Entity_Callback, currentrenderentity, NULL, NULL);
+}
+#else
+void R_ClipSpriteImage (vec3_t origin, vec3_t left, vec3_t up)
+{
+ int i;
+ mspriteframe_t *frame;
+ vec3_t points[4];
+ float fleft, fright, fdown, fup;
+ frame = NULL;
+ for (i = 0;i < 4 && currentrenderentity->frameblend[i].lerp;i++)
+ frame = currentrenderentity->model->sprdata_frames + currentrenderentity->frameblend[i].frame;
+ fleft = frame->left;
+ fdown = frame->down;
+ fright = frame->right;
+ fup = frame->up;
+ // FIXME: reverse these in loader to save time
+ fleft = -fleft;
+ fright = -fright;
+ points[0][0] = origin[0] + fdown * up[0] + fleft * left[0];points[0][1] = origin[1] + fdown * up[1] + fleft * left[1];points[0][2] = origin[2] + fdown * up[2] + fleft * left[2];
+ points[1][0] = origin[0] + fup * up[0] + fleft * left[0];points[1][1] = origin[1] + fup * up[1] + fleft * left[1];points[1][2] = origin[2] + fup * up[2] + fleft * left[2];
+ points[2][0] = origin[0] + fup * up[0] + fright * left[0];points[2][1] = origin[1] + fup * up[1] + fright * left[1];points[2][2] = origin[2] + fup * up[2] + fright * left[2];
+ points[3][0] = origin[0] + fdown * up[0] + fright * left[0];points[3][1] = origin[1] + fdown * up[1] + fright * left[1];points[3][2] = origin[2] + fdown * up[2] + fright * left[2];
+ R_Clip_AddPolygon(&points[0][0], 4, sizeof(float[3]), false, R_Entity_Callback, currentrenderentity, NULL, NULL);
+}
+#endif
+
+int R_SpriteSetup (int type, float org[3], float left[3], float up[3])
+{
+ float matrix1[3][3], matrix2[3][3], matrix3[3][3];
+
+ VectorCopy(currentrenderentity->origin, org);
+ switch(type)
+ {
+ case SPR_VP_PARALLEL_UPRIGHT:
+ // flames and such
+ // vertical beam sprite, faces view plane
+ VectorNegate(vpn, matrix3[0]);
+ matrix3[0][2] = 0;
+ VectorNormalizeFast(matrix3[0]);
+ matrix3[1][0] = matrix3[0][1];
+ matrix3[1][1] = -matrix3[0][0];
+ matrix3[1][2] = 0;
+ matrix3[2][0] = 0;
+ matrix3[2][1] = 0;
+ matrix3[2][2] = 1;
+ break;
+ case SPR_FACING_UPRIGHT:
+ // flames and such
+ // vertical beam sprite, faces viewer's origin (not the view plane)
+ VectorSubtract(currentrenderentity->origin, r_origin, matrix3[0]);
+ matrix3[0][2] = 0;
+ VectorNormalizeFast(matrix3[0]);
+ matrix3[1][0] = matrix3[0][1];
+ matrix3[1][1] = -matrix3[0][0];
+ matrix3[1][2] = 0;
+ matrix3[2][0] = 0;
+ matrix3[2][1] = 0;
+ matrix3[2][2] = 1;
+ break;
+ default:
+ Con_Printf("R_SpriteSetup: unknown sprite type %i\n", type);
+ // fall through to normal sprite
+ case SPR_VP_PARALLEL:
+ // normal sprite
+ // faces view plane
+ VectorCopy(vpn, matrix3[0]);
+ VectorNegate(vright, matrix3[1]);
+ VectorCopy(vup, matrix3[2]);
+ break;
+ case SPR_ORIENTED:
+ // bullet marks on walls
+ // ignores viewer entirely
+ AngleVectorsFLU (currentrenderentity->angles, matrix3[0], matrix3[1], matrix3[2]);
+ // nudge it toward the view, so it will be infront of the wall
+ VectorSubtract(org, vpn, org);
+ break;
+ case SPR_VP_PARALLEL_ORIENTED:
+ // I have no idea what people would use this for
+ // oriented relative to view space
+ // FIXME: test this and make sure it mimicks software
+ AngleVectorsFLU (currentrenderentity->angles, matrix1[0], matrix1[1], matrix1[2]);
+ VectorCopy(vpn, matrix2[0]);
+ VectorNegate(vright, matrix2[1]);
+ VectorCopy(vup, matrix2[2]);
+ R_ConcatRotations (matrix1[0], matrix2[0], matrix3[0]);
+ break;
+ }
+
+ if (currentrenderentity->scale != 1)
+ {
+ VectorScale(matrix3[1], currentrenderentity->scale, left);
+ VectorScale(matrix3[2], currentrenderentity->scale, up);
+ }
+ else
+ {
+ VectorCopy(matrix3[1], left);
+ VectorCopy(matrix3[2], up);
+ }
+ return false;
+}
+
+void R_ClipSprite (void)