[virglrenderer-devel] [PATCH 2/3] initial feature extension support

[Dave Airlie]

From: Dave Airlie <airlied at redhat.com>

This adds a mechanism to detect supported GL features on the
host side and use them to set the caps bits later.
---
 src/vrend_renderer.c | 60 ++++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 49 insertions(+), 11 deletions(-)

diff --git a/src/vrend_renderer.c b/src/vrend_renderer.c
index 317024a..3643550 100644
--- a/src/vrend_renderer.c
+++ b/src/vrend_renderer.c
@@ -87,6 +87,26 @@ struct global_error_state {
    enum virgl_errors last_error;
 };
 
+enum feature_name
+{
+   FEAT_START = 0,
+   FEAT_TESSELLATION = 0,
+   FEAT_END,
+};
+
+struct features {
+   int gl_ver;
+   int gles_ver;
+   const char *gl_ext;
+   const char *gles_ext;
+};
+
+static const struct features features_list[] = {
+   [FEAT_TESSELLATION] = { 400, -1, "GL_ARB_tessellation_shader", NULL },
+};
+
+#define HAVE_FEATURE(feature) (vrend_state.features[feature] == true)
+
 struct global_renderer_state {
    int gl_major_ver;
    int gl_minor_ver;
@@ -99,6 +119,7 @@ struct global_renderer_state {
    bool use_gles;
    bool use_core_profile;
 
+   bool features[FEAT_END];
    bool have_debug_cb;
    bool have_mesa_invert;
    bool have_samplers;
@@ -118,7 +139,6 @@ struct global_renderer_state {
    bool have_texture_buffer_range;
    bool have_polygon_offset_clamp;
    bool have_texture_storage;
-   bool have_tessellation;
    bool have_texture_view;
    bool have_copy_image;
    bool have_ssbo;
@@ -2565,7 +2585,7 @@ int vrend_create_shader(struct vrend_context *ctx,
    if (type > PIPE_SHADER_TESS_EVAL)
       return EINVAL;
 
-   if (!vrend_state.have_tessellation &&
+   if (!HAVE_FEATURE(FEAT_TESSELLATION) &&
        (type == PIPE_SHADER_TESS_CTRL ||
         type == PIPE_SHADER_TESS_EVAL))
       return EINVAL;
@@ -3443,7 +3463,7 @@ void vrend_draw_vbo(struct vrend_context *ctx,
    else
       glBindBuffer(GL_DRAW_INDIRECT_BUFFER, 0);
 
-   if (info->vertices_per_patch && vrend_state.have_tessellation)
+   if (info->vertices_per_patch && HAVE_FEATURE(FEAT_TESSELLATION))
       glPatchParameteri(GL_PATCH_VERTICES, info->vertices_per_patch);
 
    /* set the vertex state up now on a delay */
@@ -4526,6 +4546,25 @@ static void vrend_debug_cb(UNUSED GLenum source, GLenum type, UNUSED GLuint id,
    fprintf(stderr, "ERROR: %s\n", message);
 }
 
+static void vrend_features_init(bool gles, int gl_ver)
+{
+   for (enum feature_name feat_id = FEAT_START; feat_id < FEAT_END; feat_id++) {
+      if (gles) {
+         if (features_list[feat_id].gles_ver != -1 && gl_ver >= features_list[feat_id].gles_ver)
+            vrend_state.features[feat_id] = true;
+      } else {
+         if (features_list[feat_id].gl_ver != -1 && gl_ver >= features_list[feat_id].gl_ver)
+            vrend_state.features[feat_id] = true;
+      }
+      if (vrend_state.features[feat_id])
+         continue;
+
+      if (!gles)
+         if (epoxy_has_gl_extension(features_list[feat_id].gl_ext))
+            vrend_state.features[feat_id] = true;
+   }
+}
+
 int vrend_renderer_init(struct vrend_if_cbs *cbs, uint32_t flags)
 {
    bool gles;
@@ -4578,6 +4617,8 @@ int vrend_renderer_init(struct vrend_if_cbs *cbs, uint32_t flags)
       fprintf(stderr, "gl_version %d - compat profile\n", gl_ver);
    }
 
+   vrend_features_init(gles, gl_ver);
+
    glGetIntegerv(GL_MAX_DRAW_BUFFERS, (GLint *) &vrend_state.max_draw_buffers);
 
    if (epoxy_has_gl_extension("GL_ARB_robustness")) {
@@ -4629,9 +4670,6 @@ int vrend_renderer_init(struct vrend_if_cbs *cbs, uint32_t flags)
    if (gl_ver >= 40 || epoxy_has_gl_extension("GL_ARB_sample_shading"))
       vrend_state.have_sample_shading = true;
 
-   if (gl_ver >= 40 || epoxy_has_gl_extension("GL_ARB_tessellation_shader"))
-      vrend_state.have_tessellation = true;
-
    if (gl_ver >= 43 || epoxy_has_gl_extension("GL_ARB_texture_buffer_range"))
       vrend_state.have_texture_buffer_range = true;
 
@@ -6220,7 +6258,7 @@ void vrend_set_min_samples(struct vrend_context *ctx, unsigned min_samples)
 
 void vrend_set_tess_state(UNUSED struct vrend_context *ctx, const float tess_factors[6])
 {
-   if (vrend_state.have_tessellation) {
+   if (HAVE_FEATURE(FEAT_TESSELLATION)) {
       glPatchParameterfv(GL_PATCH_DEFAULT_OUTER_LEVEL, tess_factors);
       glPatchParameterfv(GL_PATCH_DEFAULT_INNER_LEVEL, &tess_factors[4]);
    }
@@ -7583,6 +7621,9 @@ void vrend_renderer_fill_caps(uint32_t set, uint32_t version,
       caps->v1.bset.texture_multisample = 1;
    }
 
+   if (HAVE_FEATURE(FEAT_TESSELLATION))
+      caps->v1.bset.has_tessellation_shaders = 1;
+
    if (gl_ver >= 40) {
       caps->v1.bset.indep_blend_func = 1;
       caps->v1.bset.cube_map_array = 1;
@@ -7590,7 +7631,6 @@ void vrend_renderer_fill_caps(uint32_t set, uint32_t version,
       caps->v1.bset.has_indirect_draw = 1;
       caps->v1.bset.has_sample_shading = 1;
       caps->v1.bset.has_fp64 = 1;
-      caps->v1.bset.has_tessellation_shaders = 1;
    } else {
       if (epoxy_has_gl_extension("GL_ARB_draw_buffers_blend"))
          caps->v1.bset.indep_blend_func = 1;
@@ -7606,8 +7646,6 @@ void vrend_renderer_fill_caps(uint32_t set, uint32_t version,
       if (epoxy_has_gl_extension("GL_ARB_gpu_shader_fp64") &&
           epoxy_has_gl_extension("GL_ARB_gpu_shader5"))
          caps->v1.bset.has_fp64 = 1;
-      if (epoxy_has_gl_extension("GL_ARB_tessellation_shader"))
-         caps->v1.bset.has_tessellation_shaders = 1;
    }
 
    if (gl_ver >= 42) {
@@ -7716,7 +7754,7 @@ void vrend_renderer_fill_caps(uint32_t set, uint32_t version,
       glGetIntegerv(GL_MAX_GEOMETRY_TOTAL_OUTPUT_COMPONENTS, (GLint*)&caps->v2.max_geom_total_output_components);
    }
 
-   if (epoxy_has_gl_extension("GL_ARB_tessellation_shader") || gl_ver >= 40) {
+   if (HAVE_FEATURE(FEAT_TESSELLATION)) {
       glGetIntegerv(GL_MAX_TESS_PATCH_COMPONENTS, &max);
       caps->v2.max_shader_patch_varyings = max / 4;
    } else
-- 
2.14.3