Simplify sampling a bit - preventing some indexing issues

2 files changed, 15 insertions, 15 deletions

diff --git a/data/diffraction.cl b/data/diffraction.cl
index babfc6b7..138af028 100644
--- a/data/diffraction.cl
+++ b/data/diffraction.cl
@@ -52,8 +52,8 @@ float4 get_q(int x, int y, float cx, float cy, float res, float clen, float k,
 	float ttx, tty, tt;
 	float4 q;
 
-	rx = ((float)x - cx)/res;
-	ry = ((float)y - cy)/res;
+	rx = ((float)x - sampling*cx)/(res*sampling);
+	ry = ((float)y - sampling*cy)/(res*sampling);
 
 	r = sqrt(pow(rx, 2.0) + pow(ry, 2.0));
 
@@ -134,8 +134,8 @@ kernel void diffraction(global float2 *diff, global float *tt, float k,
                        int xmin, int ymin, int sampling, local float2 *tmp)
 {
 	float ttv;
-	const int x = get_global_id(0) + xmin;
-	const int y = get_global_id(1) + ymin;
+	const int x = get_global_id(0) + (xmin*sampling);
+	const int y = get_global_id(1) + (ymin*sampling);
 	float f_lattice;
 	float2 f_molecule;
 	float4 q;
@@ -165,7 +165,7 @@ kernel void diffraction(global float2 *diff, global float *tt, float k,
 
 		diff[ax+w*ay] = sum / (sampling*sampling);
 
-		/* Leader thread also records 2theta value.
+		/* Leader thread also records the 2theta value.
 		 * This should really be averaged across all pixels, but
 		 * I strongly suspect this would be a waste of time. */
 		tt[ax+w*ay] = ttv;
diff --git a/src/diffraction-gpu.c b/src/diffraction-gpu.c
index 9057d3cc..330a676e 100644
--- a/src/diffraction-gpu.c
+++ b/src/diffraction-gpu.c
@@ -240,11 +240,6 @@ void get_diffraction_gpu(struct gpu_context *gctx, struct image *image,
 
 		size_t dims[2];
 		size_t ldims[2] = {SAMPLING, SAMPLING};
-		cl_float res = image->det.panels[p].res * SAMPLING;
-		int offsx = image->det.panels[p].min_x * SAMPLING;
-		int offsy = image->det.panels[p].min_y * SAMPLING;
-		cl_float centx = image->det.panels[p].cx * SAMPLING;
-		cl_float centy = image->det.panels[p].cy * SAMPLING;
 
 		/* In a future version of OpenCL, this could be done
 		 * with a global work offset.  But not yet... */
@@ -253,17 +248,20 @@ void get_diffraction_gpu(struct gpu_context *gctx, struct image *image,
 		dims[0] *= SAMPLING;
 		dims[1] *= SAMPLING;
 
-		clSetKernelArg(gctx->kern, 4, sizeof(cl_float), &centx);
+		clSetKernelArg(gctx->kern, 4, sizeof(cl_float),
+		               &image->det.panels[p].cx);
 		if ( err != CL_SUCCESS ) {
 			ERROR("Couldn't set arg 4: %s\n", clError(err));
 			return;
 		}
-		clSetKernelArg(gctx->kern, 5, sizeof(cl_float), &centy);
+		clSetKernelArg(gctx->kern, 5, sizeof(cl_float),
+		               &image->det.panels[p].cy);
 		if ( err != CL_SUCCESS ) {
 			ERROR("Couldn't set arg 5: %s\n", clError(err));
 			return;
 		}
-		clSetKernelArg(gctx->kern, 6, sizeof(cl_float), &res);
+		clSetKernelArg(gctx->kern, 6, sizeof(cl_float),
+		               &image->det.panels[p].res);
 		if ( err != CL_SUCCESS ) {
 			ERROR("Couldn't set arg 6: %s\n", clError(err));
 			return;
@@ -274,12 +272,14 @@ void get_diffraction_gpu(struct gpu_context *gctx, struct image *image,
 			ERROR("Couldn't set arg 7: %s\n", clError(err));
 			return;
 		}
-		clSetKernelArg(gctx->kern, 12, sizeof(cl_int), &offsx);
+		clSetKernelArg(gctx->kern, 12, sizeof(cl_int),
+		               &image->det.panels[p].min_x);
 		if ( err != CL_SUCCESS ) {
 			ERROR("Couldn't set arg 12: %s\n", clError(err));
 			return;
 		}
-		clSetKernelArg(gctx->kern, 13, sizeof(cl_int), &offsy);
+		clSetKernelArg(gctx->kern, 13, sizeof(cl_int),
+		               &image->det.panels[p].min_y);
 		if ( err != CL_SUCCESS ) {
 			ERROR("Couldn't set arg 13: %s\n", clError(err));
 			return;