On 08/20/2011 02:47 PM, Christoph Bumiller wrote:
> On 20.08.2011 22:07, Dan McCabe wrote:
>> On 08/20/2011 12:16 AM, Kenneth Graunke wrote:
>>> On 08/19/2011 05:56 PM, Eric Anholt wrote:
>>>> We have to actually convert the values on the way out. Fixes piglit
>>>> ARB_shader_objects/getuniform.
>>>> ---
>>>> src/mesa/main/uniforms.c | 32 ++++++++++++++++++++++++++++----
>>>> 1 files changed, 28 insertions(+), 4 deletions(-)
>>>>
>>>> diff --git a/src/mesa/main/uniforms.c b/src/mesa/main/uniforms.c
>>>> index cda840f..fbaa810 100644
>>>> --- a/src/mesa/main/uniforms.c
>>>> +++ b/src/mesa/main/uniforms.c
>>>> @@ -55,13 +55,11 @@ static GLenum
>>>> base_uniform_type(GLenum type)
>>>> {
>>>> switch (type) {
>>>> -#if 0 /* not needed, for now */
>>>> case GL_BOOL:
>>>> case GL_BOOL_VEC2:
>>>> case GL_BOOL_VEC3:
>>>> case GL_BOOL_VEC4:
>>>> return GL_BOOL;
>>>> -#endif
>>>> case GL_FLOAT:
>>>> case GL_FLOAT_VEC2:
>>>> case GL_FLOAT_VEC3:
>>>> @@ -408,8 +406,12 @@ get_uniform(struct gl_context *ctx, GLuint
>>>> program, GLint location,
>>>> else {
>>>> const struct gl_program_parameter *p =
>>>> &prog->Parameters->Parameters[paramPos];
>>>> + gl_constant_value (*values)[4];
>>>> GLint rows, cols, i, j, k;
>>>> GLsizei numBytes;
>>>> + GLenum storage_type;
>>>> +
>>>> + values = prog->Parameters->ParameterValues + paramPos + offset;
>>>>
>>>> get_uniform_rows_cols(p,&rows,&cols);
>>>>
>>>> @@ -421,15 +423,37 @@ get_uniform(struct gl_context *ctx, GLuint
>>>> program, GLint location,
>>>> return;
>>>> }
>>>>
>>>> + if (ctx->Const.NativeIntegers) {
>>>> + storage_type = base_uniform_type(p->DataType);
>>>> + } else {
>>>> + storage_type = GL_FLOAT;
>>>> + }
>>>> +
>>>> switch (returnType) {
>>>> case GL_FLOAT:
>>>> {
>>>> GLfloat *params = (GLfloat *) paramsOut;
>>>> k = 0;
>>>> for (i = 0; i< rows; i++) {
>>>> - const int base = paramPos + offset + i;
>>>> for (j = 0; j< cols; j++ ) {
>>>> - params[k++] =
>>>> prog->Parameters->ParameterValues[base][j].f;
>>>> + switch (storage_type) {
>>>> + case GL_FLOAT:
>>>> + params[k++] = values[i][j].f;
>>>> + break;
>>>> + case GL_INT:
>>>> + params[k++] = values[i][j].i;
>>>> + break;
>>>> + case GL_UNSIGNED_INT:
>>>> + params[k++] = values[i][j].u;
>>>> + break;
>>>> + case GL_BOOL:
>>>> + params[k++] = values[i][j].b;
>>>> + break;
>>>> + default:
>>>> + _mesa_problem(ctx, "Invalid type in glGetUniform()");
>>>> + params[k++] = 0.0;
>>>> + break;
>>>> + }
>>>> }
>>>> }
>>>> }
>>>
>>> Argh. The OpenGL specification is so unclear on what happens when you
>>> call GetUniform{f, i, ui}v on a value of a different type. Your code
>>> here assumes that it's legal to call GetUniformfv on an int/bool/uint
>>> uniform, and that the uniform's value should be implicitly converted to
>>> floating point. That seems plausible.
>>>
>>> But what about calling GetUniformiv or GetUniformuiv on a float uniform?
>>> Is it supposed to convert the float value to an int/uint? By what
>>> rounding rules...truncate? We're certainly not doing that now. If
>>> that's the proper behavior, we need your switch statement in the GL_INT
>>> and GL_UNSIGNED_INT returnType cases as well.
>>>
> The GL4.2 spec is quite clear on the issue:
> from 2.11.7:
> For all other [than boolean] uniform types, except for subroutine
> uniforms and atomic counters, the Uniform* command used must match the
> size and type of the uniform, as declared in the shader. No type
> conversions are done.
> An INVALID_OPERATION error will be generated if an attempt is made to
> use a non-matching Uniform* command.
That's for glUniform, though, which -loads- uniforms. I found no such
text for gl*Get*Uniform...
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