Cycles: Enable half float support (4 channels and 1 channel) on CUDA.

Atm OpenEXR half files benefit from this and will use only 1/2 of the memory now. More space for HDRs!

Part of my GSoC 2016.

intern/cycles/device/device_cuda.cpp

@@ -576,6 +576,7 @@ public:
 			case TYPE_UINT: format = CU_AD_FORMAT_UNSIGNED_INT32; break;
 			case TYPE_INT: format = CU_AD_FORMAT_SIGNED_INT32; break;
 			case TYPE_FLOAT: format = CU_AD_FORMAT_FLOAT; break;
+			case TYPE_HALF: format = CU_AD_FORMAT_HALF; break;
 			default: assert(0); return;
 		}
 
@@ -747,8 +748,12 @@ public:
 				}
 
 				/* Resize once */
-				if(flat_slot >= bindless_mapping.size())
-					bindless_mapping.resize(4096); /*TODO(dingto): Make this a variable */
+				if(flat_slot >= bindless_mapping.size()) {
+					/* Allocate some slots in advance, to reduce amount
+					 * of re-allocations.
+					 */
+					bindless_mapping.resize(flat_slot + 128);
+				}
 
 				/* Set Mapping and tag that we need to (re-)upload to device */
 				bindless_mapping.get_data()[flat_slot] = (uint)tex;

intern/cycles/kernel/kernel_compat_cuda.h

@@ -31,6 +31,7 @@
 #endif
 
 #include <cuda.h>
+#include <cuda_fp16.h>
 #include <float.h>
 
 /* Qualifier wrappers for different names on different devices */

intern/cycles/kernel/svm/svm_image.h

@@ -18,7 +18,7 @@ CCL_NAMESPACE_BEGIN
 
 /* Float4 textures on various devices. */
 #if defined(__KERNEL_CPU__)
-#  define TEX_NUM_FLOAT4_IMAGES	TEX_NUM_FLOAT4_CPU
+#  define TEX_NUM_FLOAT4_IMAGES		TEX_NUM_FLOAT4_CPU
 #elif defined(__KERNEL_CUDA__)
 #  if __CUDA_ARCH__ < 300
 #    define TEX_NUM_FLOAT4_IMAGES	TEX_NUM_FLOAT4_CUDA
@@ -277,8 +277,10 @@ ccl_device float4 svm_image_texture(KernelGlobals *kg, int id, float x, float y,
 	}
 #  else
 	CUtexObject tex = kernel_tex_fetch(__bindless_mapping, id);
+	/* float4, byte4 and half4 */
 	if(id < TEX_START_FLOAT_CUDA_KEPLER)
 		r = kernel_tex_image_interp_float4(tex, x, y);
+	/* float, byte and half */
 	else {
 		float f = kernel_tex_image_interp_float(tex, x, y);
 		r = make_float4(f, f, f, 1.0);

intern/cycles/util/util_half.h

@@ -33,17 +33,21 @@ CCL_NAMESPACE_BEGIN
 
 #else
 
+/* CUDA has its own half data type, no need to define then */
+#ifndef __KERNEL_CUDA__
 typedef unsigned short half;
+#endif
+
 struct half4 { half x, y, z, w; };
 
 #ifdef __KERNEL_CUDA__
 
 ccl_device_inline void float4_store_half(half *h, float4 f, float scale)
 {
-	h[0] = __float2half_rn(f.x * scale);
-	h[1] = __float2half_rn(f.y * scale);
-	h[2] = __float2half_rn(f.z * scale);
-	h[3] = __float2half_rn(f.w * scale);
+	h[0] = __float2half(f.x * scale);
+	h[1] = __float2half(f.y * scale);
+	h[2] = __float2half(f.z * scale);
+	h[3] = __float2half(f.w * scale);
 }
 
 #else

intern/cycles/util/util_texture.h

@@ -52,10 +52,10 @@ CCL_NAMESPACE_BEGIN
 /* CUDA (Kepler, Geforce 6xx and above) */
 #define TEX_NUM_FLOAT4_CUDA_KEPLER		1024
 #define TEX_NUM_BYTE4_CUDA_KEPLER		1024
-#define TEX_NUM_HALF4_CUDA_KEPLER		0
+#define TEX_NUM_HALF4_CUDA_KEPLER		1024
 #define TEX_NUM_FLOAT_CUDA_KEPLER		1024
 #define TEX_NUM_BYTE_CUDA_KEPLER		1024
-#define TEX_NUM_HALF_CUDA_KEPLER		0
+#define TEX_NUM_HALF_CUDA_KEPLER		1024
 #define TEX_START_FLOAT4_CUDA_KEPLER	0
 #define TEX_START_BYTE4_CUDA_KEPLER		TEX_NUM_FLOAT4_CUDA_KEPLER
 #define TEX_START_HALF4_CUDA_KEPLER		(TEX_NUM_FLOAT4_CUDA_KEPLER + TEX_NUM_BYTE4_CUDA_KEPLER)