vrend,feature: Check for GL_OES_viewport_array extension

This enables indexed access to viewports on GLES hosts.

v2: Also add the extension to shaders when needed

Signed-off-by: Gert Wollny <gert.wollny@collabora.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

src/vrend_renderer.c

@@ -229,7 +229,7 @@ static const  struct {
    FEAT(transform_feedback_overflow_query, 46, UNAVAIL,  "GL_ARB_transform_feedback_overflow_query" ),
    FEAT(txqs, 45, UNAVAIL,  "GL_ARB_shader_texture_image_samples" ),
    FEAT(ubo, 31, 30,  "GL_ARB_uniform_buffer_object" ),
-   FEAT(viewport_array, 41, UNAVAIL,  "GL_ARB_viewport_array" ),
+   FEAT(viewport_array, 41, UNAVAIL,  "GL_ARB_viewport_array", "GL_OES_viewport_array"),
 };
 
 struct global_renderer_state {

src/vrend_shader.c

@@ -905,6 +905,8 @@ iter_declaration(struct tgsi_iterate_context *iter,
             name_prefix = "gl_ViewportIndex";
             if (ctx->glsl_ver_required >= 140)
                ctx->shader_req_bits |= SHADER_REQ_LAYER;
+            if (ctx->cfg->use_gles)
+               ctx->shader_req_bits |= SHADER_REQ_VIEWPORT_IDX;
             break;
          }
          /* fallthrough */
@@ -1213,7 +1215,7 @@ iter_declaration(struct tgsi_iterate_context *iter,
             ctx->outputs[i].override_no_wm = true;
             ctx->outputs[i].is_int = true;
             name_prefix = "gl_ViewportIndex";
-            if (ctx->glsl_ver_required >= 140)
+            if (ctx->glsl_ver_required >= 140 || ctx->cfg->use_gles)
                ctx->shader_req_bits |= SHADER_REQ_VIEWPORT_IDX;
             break;
          }
@@ -4709,6 +4711,9 @@ static void emit_header(struct dump_ctx *ctx)
             emit_ext(ctx, "EXT_shader_framebuffer_fetch", "require");
       }
 
+      if (ctx->shader_req_bits & SHADER_REQ_VIEWPORT_IDX)
+         emit_ext(ctx, "OES_viewport_array", "require");
+
       if (ctx->prog_type == TGSI_PROCESSOR_GEOMETRY) {
          emit_ext(ctx, "EXT_geometry_shader", "require");
          if (ctx->shader_req_bits & SHADER_REQ_PSIZE)