[Mesa-dev] [PATCH 1/2] meta: Add a GLSL-based _mesa_meta_Clear() variant.
Ian Romanick
idr at freedesktop.org
Tue Jul 19 13:46:38 PDT 2011
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On 07/18/2011 09:33 AM, Eric Anholt wrote:
> This cuts out a large portion of the overhead of glClear() from
> resetting the texenv state and recomputing the fixed function
> programs. It also means less use of fixed function internally in our
> GLES2 drivers, which is rather bogus.
> ---
> src/mesa/drivers/common/meta.c | 166 ++++++++++++++++++++++++++++++++++++++++
> src/mesa/drivers/common/meta.h | 3 +
> 2 files changed, 169 insertions(+), 0 deletions(-)
>
> diff --git a/src/mesa/drivers/common/meta.c b/src/mesa/drivers/common/meta.c
> index 0e58aec..09d7186 100644
> --- a/src/mesa/drivers/common/meta.c
> +++ b/src/mesa/drivers/common/meta.c
> @@ -62,6 +62,7 @@
> #include "main/teximage.h"
> #include "main/texparam.h"
> #include "main/texstate.h"
> +#include "main/uniforms.h"
> #include "main/varray.h"
> #include "main/viewport.h"
> #include "program/program.h"
> @@ -235,6 +236,8 @@ struct clear_state
> {
> GLuint ArrayObj;
> GLuint VBO;
> + GLuint ShaderProg;
> + GLint ColorLocation;
> };
>
>
> @@ -1589,6 +1592,169 @@ _mesa_meta_Clear(struct gl_context *ctx, GLbitfield buffers)
> _mesa_meta_end(ctx);
> }
>
> +static void
> +meta_glsl_clear_init(struct gl_context *ctx, struct clear_state *clear)
> +{
> + const char *vs_source =
> + "attribute vec4 position;\n"
> + "void main()\n"
> + "{\n"
> + " gl_Position = position;\n"
> + "}\n";
> + const char *fs_source =
> + "uniform vec4 color;\n"
> + "void main()\n"
> + "{\n"
> + " gl_FragColor = color;\n"
> + "}\n";
> + GLuint vs, fs;
> +
> + if (clear->ArrayObj != 0)
> + return;
> +
> + /* create vertex array object */
> + _mesa_GenVertexArrays(1, &clear->ArrayObj);
> + _mesa_BindVertexArray(clear->ArrayObj);
> +
> + /* create vertex array buffer */
> + _mesa_GenBuffersARB(1, &clear->VBO);
> + _mesa_BindBufferARB(GL_ARRAY_BUFFER_ARB, clear->VBO);
> +
> + /* setup vertex arrays */
> + _mesa_VertexAttribPointerARB(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float),
> + (void *)0);
> + _mesa_EnableVertexAttribArrayARB(0);
> +
> + vs = _mesa_CreateShaderObjectARB(GL_VERTEX_SHADER);
> + _mesa_ShaderSourceARB(vs, 1, &vs_source, NULL);
> + _mesa_CompileShaderARB(vs);
> +
> + fs = _mesa_CreateShaderObjectARB(GL_FRAGMENT_SHADER);
> + _mesa_ShaderSourceARB(fs, 1, &fs_source, NULL);
> + _mesa_CompileShaderARB(fs);
> +
> + clear->ShaderProg = _mesa_CreateProgramObjectARB();
> + _mesa_AttachShader(clear->ShaderProg, fs);
> + _mesa_AttachShader(clear->ShaderProg, vs);
> + _mesa_BindAttribLocationARB(clear->ShaderProg, 0, "position");
> + _mesa_LinkProgramARB(clear->ShaderProg);
> +
> + _mesa_DeleteShader(fs);
> + _mesa_DeleteShader(vs);
> +
> + clear->ColorLocation = _mesa_GetUniformLocationARB(clear->ShaderProg,
> + "color");
> +}
> +
> +/**
> + * Meta implementation of ctx->Driver.Clear() in terms of polygon rendering.
> + */
> +void
> +_mesa_meta_glsl_Clear(struct gl_context *ctx, GLbitfield buffers)
> +{
> + struct clear_state *clear = &ctx->Meta->Clear;
> + /* save all state but scissor, pixel pack/unpack */
> + GLbitfield metaSave = (META_ALL -
> + META_SCISSOR -
> + META_PIXEL_STORE -
> + META_CONDITIONAL_RENDER);
> + const GLuint stencilMax = (1 << ctx->DrawBuffer->Visual.stencilBits) - 1;
> + struct gl_framebuffer *fb = ctx->DrawBuffer;
> + const float x0 = ((float)fb->_Xmin / fb->Width) * 2.0 - 1.0;
> + const float y0 = ((float)fb->_Ymin / fb->Height) * 2.0 - 1.0;
> + const float x1 = ((float)fb->_Xmax / fb->Width) * 2.0 - 1.0;
> + const float y1 = ((float)fb->_Ymax / fb->Height) * 2.0 - 1.0;
> + const float z = -invert_z(ctx->Depth.Clear);
> + struct vertex {
> + GLfloat x, y, z;
> + } verts[4];
> +
> + metaSave = (META_ALPHA_TEST |
> + META_BLEND |
> + META_DEPTH_TEST |
> + META_RASTERIZATION |
> + META_SHADER |
> + META_STENCIL_TEST |
> + META_VERTEX |
> + META_VIEWPORT |
> + META_CLAMP_FRAGMENT_COLOR);
Why is metaSave initialized twice? Also, BITS - OTHER_BITS - MORE_BITS
is non-obvious. This should result in the same compile-time constant as
BITS & ~(OTHER_BITS | MORE_BITS), right?
> +
> + if (!(buffers & BUFFER_BITS_COLOR)) {
> + /* We'll use colormask to disable color writes. Otherwise,
> + * respect color mask
> + */
> + metaSave |= META_COLOR_MASK;
> + }
> +
> + _mesa_meta_begin(ctx, metaSave);
> +
> + meta_glsl_clear_init(ctx, clear);
> +
> + _mesa_UseProgramObjectARB(clear->ShaderProg);
> + _mesa_Uniform4fvARB(clear->ColorLocation, 1,
> + ctx->Color.ClearColorUnclamped);
> +
> + _mesa_BindVertexArray(clear->ArrayObj);
> + _mesa_BindBufferARB(GL_ARRAY_BUFFER_ARB, clear->VBO);
> +
> + /* GL_COLOR_BUFFER_BIT */
> + if (buffers & BUFFER_BITS_COLOR) {
> + /* leave colormask, glDrawBuffer state as-is */
> +
> + /* Clears never have the color clamped. */
> + _mesa_ClampColorARB(GL_CLAMP_FRAGMENT_COLOR, GL_FALSE);
> + }
> + else {
> + ASSERT(metaSave & META_COLOR_MASK);
> + _mesa_ColorMask(GL_FALSE, GL_FALSE, GL_FALSE, GL_FALSE);
> + }
> +
> + /* GL_DEPTH_BUFFER_BIT */
> + if (buffers & BUFFER_BIT_DEPTH) {
> + _mesa_set_enable(ctx, GL_DEPTH_TEST, GL_TRUE);
> + _mesa_DepthFunc(GL_ALWAYS);
> + _mesa_DepthMask(GL_TRUE);
> + }
> + else {
> + assert(!ctx->Depth.Test);
> + }
> +
> + /* GL_STENCIL_BUFFER_BIT */
> + if (buffers & BUFFER_BIT_STENCIL) {
> + _mesa_set_enable(ctx, GL_STENCIL_TEST, GL_TRUE);
> + _mesa_StencilOpSeparate(GL_FRONT_AND_BACK,
> + GL_REPLACE, GL_REPLACE, GL_REPLACE);
> + _mesa_StencilFuncSeparate(GL_FRONT_AND_BACK, GL_ALWAYS,
> + ctx->Stencil.Clear & stencilMax,
> + ctx->Stencil.WriteMask[0]);
> + }
> + else {
> + assert(!ctx->Stencil.Enabled);
> + }
> +
> + /* vertex positions */
> + verts[0].x = x0;
> + verts[0].y = y0;
> + verts[0].z = z;
> + verts[1].x = x1;
> + verts[1].y = y0;
> + verts[1].z = z;
> + verts[2].x = x1;
> + verts[2].y = y1;
> + verts[2].z = z;
> + verts[3].x = x0;
> + verts[3].y = y1;
> + verts[3].z = z;
> +
> + /* upload new vertex data */
> + _mesa_BufferDataARB(GL_ARRAY_BUFFER_ARB, sizeof(verts), verts,
> + GL_DYNAMIC_DRAW_ARB);
> +
> + /* draw quad */
> + _mesa_DrawArrays(GL_TRIANGLE_FAN, 0, 4);
> +
> + _mesa_meta_end(ctx);
> +}
>
> /**
> * Meta implementation of ctx->Driver.CopyPixels() in terms
> diff --git a/src/mesa/drivers/common/meta.h b/src/mesa/drivers/common/meta.h
> index b0797d3..32c789e 100644
> --- a/src/mesa/drivers/common/meta.h
> +++ b/src/mesa/drivers/common/meta.h
> @@ -43,6 +43,9 @@ extern void
> _mesa_meta_Clear(struct gl_context *ctx, GLbitfield buffers);
>
> extern void
> +_mesa_meta_glsl_Clear(struct gl_context *ctx, GLbitfield buffers);
> +
> +extern void
> _mesa_meta_CopyPixels(struct gl_context *ctx, GLint srcx, GLint srcy,
> GLsizei width, GLsizei height,
> GLint dstx, GLint dsty, GLenum type);
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