Use Glad for Android frontend

CMakeLists.txt

@@ -388,7 +388,11 @@ elseif(PLATFORM STREQUAL "android")
     target_include_directories(butterscotch PRIVATE ${CMAKE_SOURCE_DIR}/src/gl)
     target_include_directories(butterscotch PRIVATE ${CMAKE_SOURCE_DIR}/src/gl_common)
     target_include_directories(butterscotch PRIVATE ${CMAKE_SOURCE_DIR}/src/image)
-    add_compile_definitions(ENABLE_GLES PLATFORM_ANDROID)
+    add_compile_definitions(PLATFORM_ANDROID)
+
+    # GLAD
+    add_library(glad STATIC vendor/glad/src/glad.c)
+    target_include_directories(glad PUBLIC vendor/glad/include)
 
     # Butterscotch VM/interpreter profiler
     option(ENABLE_VM_GML_PROFILER "Enable Butterscotch VM/interpreter profiler" ON)
@@ -429,9 +433,9 @@ elseif(PLATFORM STREQUAL "android")
 
     # Android NDK system libraries:
     # - log: __android_log_*
-    # - GLESv3: OpenGL ES 3.0 functions
+    # - EGL: eglGetProcAddress used by the Glad GLES2 loader
     # - OpenSLES: miniaudio's OpenSL ES backend (it dlopen's libaaudio.so at runtime when available, so no link-time aaudio dep)
-    target_link_libraries(butterscotch PRIVATE log GLESv3 OpenSLES bzip2 stb_ds sha1 stb_vorbis)
+    target_link_libraries(butterscotch PRIVATE glad log EGL OpenSLES bzip2 stb_ds sha1 stb_vorbis)
 elseif(PLATFORM STREQUAL "ps2")
     file(GLOB DEBUG_FONT_SOURCES src/debug_font/*.c)
     target_sources(butterscotch PRIVATE ${DEBUG_FONT_SOURCES})

src/android/main.c

@@ -5,7 +5,9 @@
 #include <errno.h>
 #include <sys/stat.h>
 #include <android/log.h>
-#include <GLES3/gl3.h>
+#include <dlfcn.h>
+#include <EGL/egl.h>
+#include <glad/glad.h>
 
 #include "common.h"
 #include "data_win.h"
@@ -406,6 +408,13 @@ JNIEXPORT jboolean JNICALL JNI_FN(startRunner)(JNIEnv* env, MAYBE_UNUSED jclass
         return JNI_FALSE;
     }
     gHostFramebuffer = (GLuint) jHostFramebuffer;
+
+    if (!gladLoadGLES2Loader((GLADloadproc)eglGetProcAddress)) {
+        LOGE("Failed to load OpenGL ES via Glad");
+        return JNI_FALSE;
+    }
+    LOGI("GL Version: %s", glGetString(GL_VERSION));
+
     const char* dataWinPath = (*env)->GetStringUTFChars(env, jDataWinPath, nullptr);
     const char* savesPath   = (*env)->GetStringUTFChars(env, jSavesPath,   nullptr);
     char** gameArgs = nullptr;

src/gl/gl_renderer.c

@@ -2,7 +2,7 @@
 #include "matrix_math.h"
 #include "text_utils.h"
 
-#if defined(__EMSCRIPTEN__) || defined(__ANDROID__)
+#if defined(__EMSCRIPTEN__)
 #include <GLES3/gl3.h>
 #else
 #include <glad/glad.h>
@@ -51,15 +51,15 @@ static const char* baseFragmentShader =
 // ===[ Runtime OpenGL extension checks ]===
 
 static bool hasFBO() {
-#if !defined(__EMSCRIPTEN__) && !defined(__ANDROID__)
+#if !defined(__EMSCRIPTEN__)
     return (glGenFramebuffers || glGenFramebuffersEXT);
 #else
     return true;
 #endif
 }
 
 static bool hasVAO() {
-#if !defined(__EMSCRIPTEN__) && !defined(__ANDROID__)
+#if !defined(__EMSCRIPTEN__)
     return (glGenVertexArrays || glGenVertexArraysOES);
 #else
     return true;

src/gl/gl_renderer.h

@@ -4,7 +4,7 @@
 #include "common.h"
 #include "renderer.h"
 #include "runner.h"
-#if defined(__EMSCRIPTEN__) || defined(__ANDROID__)
+#if defined(__EMSCRIPTEN__)
 #include <GLES3/gl3.h>
 #else
 #include <glad/glad.h>

src/gl_common/gl_common.h

@@ -4,13 +4,14 @@
 #include "common.h"
 #include <stdint.h>
 
-#if defined(__EMSCRIPTEN__) || defined(__ANDROID__)
+#if defined(__EMSCRIPTEN__)
 #include <GLES3/gl3.h>
-#elif PLATFORM_PS3
+#elif defined(__ANDROID__) || !defined(PLATFORM_PS3)
+#include <glad/glad.h>
+#endif
+#if PLATFORM_PS3
 #include "ps3gl.h"
 #include "rsxutil.h"
-#else
-#include <glad/glad.h>
 #endif
 
 // ===[ Letterbox blit ]===

src/gl_common/gl_wrappers.h

@@ -1,4 +1,4 @@
-#if !defined(_BS_GL_WRAPPERS_H_) && !defined(__EMSCRIPTEN__) && !defined(PLATFORM_PS3) && !defined(__ANDROID__)
+#if !defined(_BS_GL_WRAPPERS_H_) && !defined(__EMSCRIPTEN__) && !defined(PLATFORM_PS3)
 #define _BS_GL_WRAPPERS_H_
 
 static inline void rt_glBindVertexArray(GLuint vao) {