On Sat, 20 Aug 2011 00:16:05 -0700, Kenneth Graunke <kenn...@whitecape.org>
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.Note that I came up with the testcase to improve our coverage after the bug was caught by a ogles2conform case. I'm confident in this behavior of glGetUniform being the correct one. > 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. Ooh, good point. We were just casting to int, while it looks like for glGetIntegerv, we do IROUND. I suspect the correct answer is IROUND in that case? > We also do need it for the GL_DOUBLE returnType case. (Admittedly > that's a GL 4 function we don't implement, but we may as well get it > right now...) The GL_DOUBLE case was already completely broken unrelated to native integers, nor is it testable in Mesa currently, so I didn't touch it.
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