GPU: replace GLEW with libepoxy

With libepoxy we can choose between EGL and GLX at runtime, as well as
dynamically open EGL and GLX libraries without linking to them.

This will make it possible to build with Wayland, EGL, GLVND support while
still running on systems that only have X11, GLX and libGL. It also paves
the way for headless rendering through EGL.

libepoxy is a new library dependency, and is included in the precompiled
libraries. GLEW is no longer a dependency, and WITH_SYSTEM_GLEW was removed.

Includes contributions by Brecht Van Lommel, Ray Molenkamp, Campbell Barton
and Sergey Sharybin.

Ref T76428

Differential Revision: https://developer.blender.org/D15291

1 files changed, 7 insertions, 7 deletions

diff --git a/source/blender/gpu/opengl/gl_shader.cc b/source/blender/gpu/opengl/gl_shader.cc
index ccdf10c1ed2..a08019cc707 100644
--- a/source/blender/gpu/opengl/gl_shader.cc
+++ b/source/blender/gpu/opengl/gl_shader.cc
@@ -545,7 +545,7 @@ std::string GLShader::vertex_interface_declare(const ShaderCreateInfo &info) con
     if (!GLContext::native_barycentric_support) {
       /* Disabled or unsupported. */
     }
-    else if (GLEW_AMD_shader_explicit_vertex_parameter) {
+    else if (epoxy_has_gl_extension("GL_AMD_shader_explicit_vertex_parameter")) {
       /* Need this for stable barycentric. */
       ss << "flat out vec4 gpu_pos_flat;\n";
       ss << "out vec4 gpu_pos;\n";
@@ -581,7 +581,7 @@ std::string GLShader::fragment_interface_declare(const ShaderCreateInfo &info) c
       ss << "noperspective in vec3 gpu_BaryCoordNoPersp;\n";
       ss << "#define gpu_position_at_vertex(v) gpu_pos[v]\n";
     }
-    else if (GLEW_AMD_shader_explicit_vertex_parameter) {
+    else if (epoxy_has_gl_extension("GL_AMD_shader_explicit_vertex_parameter")) {
       std::cout << "native" << std::endl;
       /* NOTE(fclem): This won't work with geometry shader. Hopefully, we don't need geometry
        * shader workaround if this extension/feature is detected. */
@@ -612,7 +612,7 @@ std::string GLShader::fragment_interface_declare(const ShaderCreateInfo &info) c
   if (info.early_fragment_test_) {
     ss << "layout(early_fragment_tests) in;\n";
   }
-  if (GLEW_ARB_conservative_depth) {
+  if (epoxy_has_gl_extension("GL_ARB_conservative_depth")) {
     ss << "layout(" << to_string(info.depth_write_) << ") out float gl_FragDepth;\n";
   }
   ss << "\n/* Outputs. */\n";
@@ -805,7 +805,7 @@ static char *glsl_patch_default_get()
 
   size_t slen = 0;
   /* Version need to go first. */
-  if (GLEW_VERSION_4_3) {
+  if (epoxy_gl_version() >= 43) {
     STR_CONCAT(patch, slen, "#version 430\n");
   }
   else {
@@ -816,8 +816,8 @@ static char *glsl_patch_default_get()
    * don't use an extension for something already available! */
   if (GLContext::texture_gather_support) {
     STR_CONCAT(patch, slen, "#extension GL_ARB_texture_gather: enable\n");
-    /* Some drivers don't agree on GLEW_ARB_texture_gather and the actual support in the
-     * shader so double check the preprocessor define (see T56544). */
+    /* Some drivers don't agree on epoxy_has_gl_extension("GL_ARB_texture_gather") and the actual
+     * support in the shader so double check the preprocessor define (see T56544). */
     STR_CONCAT(patch, slen, "#ifdef GL_ARB_texture_gather\n");
     STR_CONCAT(patch, slen, "#  define GPU_ARB_texture_gather\n");
     STR_CONCAT(patch, slen, "#endif\n");
@@ -835,7 +835,7 @@ static char *glsl_patch_default_get()
     STR_CONCAT(patch, slen, "#extension GL_ARB_texture_cube_map_array : enable\n");
     STR_CONCAT(patch, slen, "#define GPU_ARB_texture_cube_map_array\n");
   }
-  if (GLEW_ARB_conservative_depth) {
+  if (epoxy_has_gl_extension("GL_ARB_conservative_depth")) {
     STR_CONCAT(patch, slen, "#extension GL_ARB_conservative_depth : enable\n");
   }
   if (GPU_shader_image_load_store_support()) {