On 01/02/2012 09:18 AM, Marek Olšák wrote:
On Mon, Jan 2, 2012 at 5:56 PM, Dave Airlie<airl...@gmail.com> wrote:
On Mon, Jan 2, 2012 at 4:40 PM, Marek Olšák<mar...@gmail.com> wrote:
On Mon, Jan 2, 2012 at 3:31 PM, Dave Airlie<airl...@gmail.com> wrote:
On Mon, Jan 2, 2012 at 1:07 PM, Marek Olšák<mar...@gmail.com> wrote:
Fetching int as float and vice versa is not allowed.
Fetching unsigned int as signed int and vice versa is not allowed either.
The first is true, the second isn't, otherwise I'd have implemented
this that way.
Doing conversions like that isn't allowed in OpenGL.
I don't have chapter/verse but EXT_texture_integer doesn't seem to
disallow this.
EXT_texture_integer doesn't, but that extension doesn't define the new
GLSL samplers, it only requires EXT_gpu_shader4.
See this part from EXT_gpu_shader4 (modifications to section 8.7 of
the GLSL spec):
Table 8.xxx lists the supported combinations of sampler types and
texture internal formats.
texture
internal default (float) integer unsigned integer
format sampler sampler sampler
float vec4 n/a n/a
normalized vec4 n/a n/a
signed int n/a ivec4 n/a
unsigned int n/a n/a uvec4
That is, no conversions are allowed. The pack/unpack stuff is
different, because it doesn't involve shaders. I have no opinion on
whether we should be that strict in u_format or not. Being strict may
later prevent making programming mistakes though.
Did you mean samplers instead of shaders in that sentence? if so I
probably agree that its fine then.
I am not sure right now what the restrictions on vertex attribs are,
so yes, I meant samplers.
Signed and unsigned integer data can be supplied to float attributes via
glVertexAttribPointer. Whether the data is interpreted as normalized or
not depends on a parameter to that function.
Signed and unsigned integer data can be supplied to int and uint
attributes via glVertexAttribIPointer. If the signedness of the data
doesn't match that of the attribute, the result is undefined. There's a
bit about that in the description of glVertexAttribI in the GL3 spec.
So, I think it should work the same as for textures.
Marek
Also I'd agree with starting simple and only enabling the conversions
if something comes up later, so with that,
Reviewed-by: Dave Airlie<airl...@redhat.com>
Dave.
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