Cycles: Add support for bindless textures.

This adds support for CUDA Texture objects (also known as Bindless textures) for Kepler GPUs (Geforce 6xx and above).
This is used for all 2D/3D textures, data still uses arrays as before.

User benefits:
* No more limits of image textures on Kepler.
 We had 5 float4 and 145 byte4 slots there before, now we have 1024 float4 and 1024 byte4.
 This can be extended further if we need to (just change the define).

* Single channel textures slots (byte and float) are now supported on Kepler as well (1024 slots for each type).

ToDo / Issues:
* 3D textures don't work yet, at least don't show up during render. I have no idea whats wrong yet.
* Dynamically allocate bindless_mapping array?

I hope Fermi still works fine, but that should be tested on a Fermi card before pushing to master.

Part of my GSoC 2016.

Reviewers: sergey, #cycles, brecht

Subscribers: swerner, jtheninja, brecht, sergey

Differential Revision: https://developer.blender.org/D1999

1 files changed, 17 insertions, 8 deletions

diff --git a/intern/cycles/kernel/kernel_compat_cuda.h b/intern/cycles/kernel/kernel_compat_cuda.h
index d10d3255e1b..42314756f02 100644
--- a/intern/cycles/kernel/kernel_compat_cuda.h
+++ b/intern/cycles/kernel/kernel_compat_cuda.h
@@ -67,20 +67,29 @@ typedef texture<uchar4, 2, cudaReadModeNormalizedFloat> texture_image_uchar4;
 
 /* Macros to handle different memory storage on different devices */
 
-/* In order to use full 6GB of memory on Titan cards, use arrays instead
- * of textures. On earlier cards this seems slower, but on Titan it is
- * actually slightly faster in tests. */
+/* On Fermi cards (4xx and 5xx), we use regular textures for both data and images.
+ * On Kepler (6xx) and above, we use Bindless Textures for images and arrays for data.
+ *
+ * Arrays are necessary in order to use the full VRAM on newer cards, and it's slightly faster.
+ * Using Arrays on Fermi turned out to be slower.*/
+
+/* Fermi */
 #if __CUDA_ARCH__ < 300
 #  define __KERNEL_CUDA_TEX_STORAGE__
-#endif
-
-#ifdef __KERNEL_CUDA_TEX_STORAGE__
 #  define kernel_tex_fetch(t, index) tex1Dfetch(t, index)
+
+#  define kernel_tex_image_interp(t, x, y) tex2D(t, x, y)
+#  define kernel_tex_image_interp_3d(t, x, y, z) tex3D(t, x, y, z)
+
+/* Kepler */
 #else
 #  define kernel_tex_fetch(t, index) t[(index)]
+
+#  define kernel_tex_image_interp_float4(t, x, y) tex2D<float4>(t, x, y)
+#  define kernel_tex_image_interp_float(t, x, y) tex2D<float>(t, x, y)
+#  define kernel_tex_image_interp_3d_float4(t, x, y, z) tex3D<float4>(t, x, y, z)
+#  define kernel_tex_image_interp_3d_float(t, x, y, z) tex3D<float>(t, x, y, z)
 #endif
-#define kernel_tex_image_interp(t, x, y) tex2D(t, x, y)
-#define kernel_tex_image_interp_3d(t, x, y, z) tex3D(t, x, y, z)
 
 #define kernel_data __data