Mesa (gallium-0.2): i965: asst. fixes, work-arounds for FBOs and render to texture

[Alan Hourihane]

Module: Mesa
Branch: gallium-0.2
Commit: 947d1c5b2a70c0eafa4c408b47607574a2908468
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=947d1c5b2a70c0eafa4c408b47607574a2908468

Author: Brian Paul <brianp at vmware.com>
Date:   Wed Jan 14 16:42:19 2009 -0700

i965: asst. fixes, work-arounds for FBOs and render to texture

OpenGL allows mixing and matching depth and stencil renderbuffers in
framebuffer objects while the hardware really only supports interleaved
depth/stencil buffers.  This makes for some tricky buffer management.

An extra wrinkle is the situation where the user allocates a 16bpp depth
texture or renderbuffer then tries to render to it along with a stencil
buffer.  We'd have to promote the 16bpp Z values to 24-bit Z values and
mix in the stencil values to setup the depth/stencil renderbuffer.

There's no support for that now, so always allocate 32bpp depth textures/
renderbuffers for now.

---

 src/mesa/drivers/dri/intel/intel_depthstencil.c |    6 ++++++
 src/mesa/drivers/dri/intel/intel_fbo.c          |    7 +++++++
 src/mesa/drivers/dri/intel/intel_tex_format.c   |   10 ++++++++--
 3 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/src/mesa/drivers/dri/intel/intel_depthstencil.c b/src/mesa/drivers/dri/intel/intel_depthstencil.c
index f43b9ae..354b3bf 100644
--- a/src/mesa/drivers/dri/intel/intel_depthstencil.c
+++ b/src/mesa/drivers/dri/intel/intel_depthstencil.c
@@ -110,7 +110,10 @@ intel_unpair_depth_stencil(GLcontext *ctx, struct intel_renderbuffer *irb)
 	 ASSERT(stencilIrb->PairedDepth == rb->Name);
 	 intel_renderbuffer_map(intel, rb);
 	 intel_renderbuffer_map(intel, stencilRb);
+#if 0
+         /* disable for now */
 	 _mesa_extract_stencil(ctx, rb, stencilRb);
+#endif
 	 intel_renderbuffer_unmap(intel, stencilRb);
 	 intel_renderbuffer_unmap(intel, rb);
          stencilIrb->PairedDepth = 0;
@@ -132,7 +135,10 @@ intel_unpair_depth_stencil(GLcontext *ctx, struct intel_renderbuffer *irb)
 	 ASSERT(depthIrb->PairedStencil == rb->Name);
 	 intel_renderbuffer_map(intel, rb);
 	 intel_renderbuffer_map(intel, depthRb);
+#if 0
+         /* disable for now */
 	 _mesa_extract_stencil(ctx, depthRb, rb);
+#endif
 	 intel_renderbuffer_unmap(intel, depthRb);
 	 intel_renderbuffer_unmap(intel, rb);
          depthIrb->PairedStencil = 0;
diff --git a/src/mesa/drivers/dri/intel/intel_fbo.c b/src/mesa/drivers/dri/intel/intel_fbo.c
index 93fc845..54f2fa5 100644
--- a/src/mesa/drivers/dri/intel/intel_fbo.c
+++ b/src/mesa/drivers/dri/intel/intel_fbo.c
@@ -248,11 +248,18 @@ intel_alloc_renderbuffer_storage(GLcontext * ctx, struct gl_renderbuffer *rb,
       cpp = 4;
       break;
    case GL_DEPTH_COMPONENT16:
+#if 0
       rb->_ActualFormat = GL_DEPTH_COMPONENT16;
       rb->DataType = GL_UNSIGNED_SHORT;
       rb->DepthBits = 16;
       cpp = 2;
       break;
+#else
+      /* fall-through.
+       * 16bpp depth renderbuffer can't be paired with a stencil buffer so
+       * always used combined depth/stencil format.
+       */
+#endif
    case GL_DEPTH_COMPONENT:
    case GL_DEPTH_COMPONENT24:
    case GL_DEPTH_COMPONENT32:
diff --git a/src/mesa/drivers/dri/intel/intel_tex_format.c b/src/mesa/drivers/dri/intel/intel_tex_format.c
index 2be060d..5e418ac 100644
--- a/src/mesa/drivers/dri/intel/intel_tex_format.c
+++ b/src/mesa/drivers/dri/intel/intel_tex_format.c
@@ -134,8 +134,14 @@ intelChooseTextureFormat(GLcontext * ctx, GLint internalFormat,
    case GL_DEPTH_COMPONENT16:
    case GL_DEPTH_COMPONENT24:
    case GL_DEPTH_COMPONENT32:
+#if 0
       return &_mesa_texformat_z16;
-
+#else
+      /* fall-through.
+       * 16bpp depth texture can't be paired with a stencil buffer so
+       * always used combined depth/stencil format.
+       */
+#endif
    case GL_DEPTH_STENCIL_EXT:
    case GL_DEPTH24_STENCIL8_EXT:
       return &_mesa_texformat_s8_z24;
@@ -158,7 +164,7 @@ intelChooseTextureFormat(GLcontext * ctx, GLint internalFormat,
    case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT1_EXT:
    case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT3_EXT:
    case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT5_EXT:
-     return &_mesa_texformat_srgb_dxt1;
+      return &_mesa_texformat_srgb_dxt1;
 #endif
 
    default: