[Mesa-dev] [PATCH 1/2] _mesa_meta_GenerateMipmap: Support all texture targets by generating shaders at runtime

[Ian Romanick]

On 09/11/2012 05:36 PM, Brian Paul wrote:
> On 09/11/2012 01:56 AM, Ian Romanick wrote:
>> On 09/05/2012 05:42 AM, Anuj Phogat wrote:
>>> glsl path of _mesa_meta_GenerateMipmap() function would require
>>> different fragment
>>> shaders depending on the texture target. This patch adds the code to
>>> generate
>>> appropriate fragment shader programs at run time.
>>> Fixes https://bugs.freedesktop.org/show_bug.cgi?id=54296
>>>
>>> NOTE: This is a candidate for stable branches.
>>>
>>> Signed-off-by: Anuj Phogat <anuj.phogat at gmail.com>
>>> ---
>>> src/mesa/drivers/common/meta.c | 100
>>> +++++++++++++++++++++++++++++++++++----
>>> 1 files changed, 89 insertions(+), 11 deletions(-)
>>>
>>> diff --git a/src/mesa/drivers/common/meta.c
>>> b/src/mesa/drivers/common/meta.c
>>> index 36672a7..7d701f4 100644
>>> --- a/src/mesa/drivers/common/meta.c
>>> +++ b/src/mesa/drivers/common/meta.c
>>> @@ -286,6 +286,15 @@ struct gen_mipmap_state
>>> GLuint IntegerShaderProg;
>>> };
>>>
>>> +/**
>>> + * State for GLSL texture sampler which is used to generate fragment
>>> + * shader in _mesa_meta_generate_mipmap().
>>> + */
>>> +struct glsl_sampler {
>>> + const char *type;
>>> + const char *func;
>>> + const char *texcoords;
>>> +};
>>>
>>> /**
>>> * State for texture decompression
>>> @@ -2974,7 +2983,7 @@ setup_texture_coords(GLenum faceTarget,
>>>
>>> static void
>>> setup_ff_generate_mipmap(struct gl_context *ctx,
>>> - struct gen_mipmap_state *mipmap)
>>> + struct gen_mipmap_state *mipmap)
>>> {
>>> struct vertex {
>>> GLfloat x, y, tex[3];
>>> @@ -3004,12 +3013,53 @@ setup_ff_generate_mipmap(struct gl_context
>>> *ctx,
>>>
>>>
>>> static void
>>> +setup_texture_sampler(GLenum target, struct glsl_sampler *sampler)
>>> +{
>>> + switch(target) {
>>> + case GL_TEXTURE_1D:
>>> + sampler->type = "sampler1D";
>>> + sampler->func = "texture1D";
>>> + sampler->texcoords = "texCoords.x";
>>> + break;
>>> + case GL_TEXTURE_2D:
>>> + sampler->type = "sampler2D";
>>> + sampler->func = "texture2D";
>>> + sampler->texcoords = "texCoords.xy";
>>> + break;
>>> + case GL_TEXTURE_3D:
>>> + sampler->type = "sampler3D";
>>> + sampler->func = "texture3D";
>>> + sampler->texcoords = "texCoords";
>>> + break;
>>> + case GL_TEXTURE_CUBE_MAP:
>>> + sampler->type = "samplerCube";
>>> + sampler->func = "textureCube";
>>> + sampler->texcoords = "texCoords";
>>> + break;
>>> + case GL_TEXTURE_1D_ARRAY:
>>> + sampler->type = "sampler1DARRAY";
>>> + sampler->texcoords = "texCoords.xy";
>>> + break;
>>> + case GL_TEXTURE_2D_ARRAY:
>>> + sampler->type = "sampler2DARRAY";
>>> + sampler->texcoords = "texCoords";
>>> + break;
>>> + default:
>>> + /* unexpected texture target */
>>> + return;
>>> + }
>>> +}
>>> +
>>> +
>>> +static void
>>> setup_glsl_generate_mipmap(struct gl_context *ctx,
>>> - struct gen_mipmap_state *mipmap)
>>> + struct gen_mipmap_state *mipmap,
>>> + GLenum target)
>>> {
>>> struct vertex {
>>> GLfloat x, y, tex[3];
>>> };
>>> + struct glsl_sampler sampler;
>>>
>>> static const char *vs_source =
>>> "attribute vec2 position;\n"
>>> @@ -3020,14 +3070,17 @@ setup_glsl_generate_mipmap(struct gl_context
>>> *ctx,
>>> " texCoords = textureCoords;\n"
>>> " gl_Position = vec4(position, 0.0, 1.0);\n"
>>> "}\n";
>>> - static const char *fs_source =
>>> - "uniform sampler2D tex2d;\n"
>>> + static const char *fs_template =
>>> + "#define SAMPLER_TYPE %s\n"
>>> + "#define SAMPLER_FUNCTION %s\n"
>>> + "#define TEX_COORDS %s\n"
>>
>> Since each of these is only used once, why use the extra #defines? I
>> believe we can use $ to force the arguments to have the same order.
>>
>> static const char *fs_template =
>> "uniform %1$s texSampler;\n"
>> "varying vec3 texCoords;\n"
>> "void main()\n"
>> "{\n"
>> " gl_FragColor = %2$s(texSampler, %3$s);\n"
>> "}\n";
>>
>> This works like the {0} formatting in Python.
>>
>> Brian, do you know if this is supported on Windows?
>
> I don't think so.  I see no mention of it in the MSDN docs and the Linux
> man page says "The C99 standard does not include the style using  '$',
> which comes from the Single Unix Specification."

Dang. :(

> To be honest, I wasn't even aware of the $ syntax until you wrote this.

It was added almost 20 years ago for internationalization.  It allows 
you to have per-language format strings with replacements in different 
places to account for word ordering rules in different languages.

>
> -Brian
>