From 06cc738b008cb0017965b14013c3039bdd430df8 Mon Sep 17 00:00:00 2001
From: Vicki Pfau <vi@endrift.com>
Date: Tue, 14 May 2019 23:33:54 -0700
Subject: [PATCH] GBA Video: Fix VAOs on Nvidia

---
 src/gba/renderers/gl.c      |  6 +++++-
 src/platform/opengl/gles2.c | 16 ++++++++++++----
 2 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/src/gba/renderers/gl.c b/src/gba/renderers/gl.c
index d28510014..5a8521d81 100644
--- a/src/gba/renderers/gl.c
+++ b/src/gba/renderers/gl.c
@@ -428,7 +428,6 @@ void _compileShader(struct GBAVideoGLRenderer* glRenderer, struct GBAVideoGLShad
 	glBindBuffer(GL_ARRAY_BUFFER, glRenderer->vbo);
 	GLuint positionLocation = glGetAttribLocation(program, "position");
 	glVertexAttribPointer(positionLocation, 2, GL_INT, GL_FALSE, 0, NULL);
-	glEnableVertexAttribArray(positionLocation);
 
 	size_t i;
 	for (i = 0; uniforms[i].name; ++i) {
@@ -1084,6 +1083,7 @@ static void _compositeLayer(struct GBAVideoGLRenderer* renderer, GLuint tex, GLu
 	glUniform1i(uniforms[GBA_GL_COMPOSITE_OLDOLDFLAGS], 4);
 	glUniform1i(uniforms[GBA_GL_COMPOSITE_WINDOW], 5);
 	glDrawBuffers(4, (GLenum[]) { GL_COLOR_ATTACHMENT0, GL_COLOR_ATTACHMENT1, GL_COLOR_ATTACHMENT2, GL_COLOR_ATTACHMENT3 });
+	glEnableVertexAttribArray(0);
 	glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
 	glDrawBuffers(1, (GLenum[]) { GL_COLOR_ATTACHMENT0 });
 }
@@ -1113,6 +1113,7 @@ void _finalizeLayers(struct GBAVideoGLRenderer* renderer, int y) {
 	glUniform1i(uniforms[GBA_GL_FINALIZE_LAYERFLAGS], 1);
 	glUniform1i(uniforms[GBA_GL_FINALIZE_OLDLAYER], 2);
 	glUniform1i(uniforms[GBA_GL_FINALIZE_OLDFLAGS], 3);
+	glEnableVertexAttribArray(0);
 	glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
 	glBindFramebuffer(GL_FRAMEBUFFER, 0);
 }
@@ -1185,6 +1186,7 @@ void GBAVideoGLRendererDrawSprite(struct GBAVideoGLRenderer* renderer, struct GB
 		glUniform3f(uniforms[GBA_GL_OBJ_OBJWIN], 0, 0, 0);
 		glDrawBuffers(2, (GLenum[]) { GL_COLOR_ATTACHMENT0, GL_COLOR_ATTACHMENT1 });
 	}
+	glEnableVertexAttribArray(0);
 	glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
 	glDrawBuffers(1, (GLenum[]) { GL_COLOR_ATTACHMENT0 });
 }
@@ -1221,6 +1223,7 @@ void GBAVideoGLRendererDrawBackgroundMode0(struct GBAVideoGLRenderer* renderer,
 		                                     background->target1 | (background->target2 * 2) | (renderer->blendEffect * 4),
 		                                     renderer->blendEffect == BLEND_ALPHA ? renderer->blda : renderer->bldy, renderer->bldb);
 	glDrawBuffers(2, (GLenum[]) { GL_COLOR_ATTACHMENT0, GL_COLOR_ATTACHMENT1 });
+	glEnableVertexAttribArray(0);
 	glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
 	glDrawBuffers(1, (GLenum[]) { GL_COLOR_ATTACHMENT0 });
 
@@ -1277,6 +1280,7 @@ void GBAVideoGLRendererDrawBackgroundMode2(struct GBAVideoGLRenderer* renderer,
 		});
 	}
 	glDrawBuffers(2, (GLenum[]) { GL_COLOR_ATTACHMENT0, GL_COLOR_ATTACHMENT1 });
+	glEnableVertexAttribArray(0);
 	glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
 	glDrawBuffers(1, (GLenum[]) { GL_COLOR_ATTACHMENT0 });
 
diff --git a/src/platform/opengl/gles2.c b/src/platform/opengl/gles2.c
index da09ecd60..d51dd568f 100644
--- a/src/platform/opengl/gles2.c
+++ b/src/platform/opengl/gles2.c
@@ -135,6 +135,15 @@ static void mGLES2ContextInit(struct VideoBackend* v, WHandle handle) {
 	uniforms[3].max.fvec3[2] = 1.0f;
 	mGLES2ShaderInit(&context->initialShader, _vertexShader, _fragmentShader, -1, -1, false, uniforms, 4);
 	mGLES2ShaderInit(&context->finalShader, 0, 0, 0, 0, false, 0, 0);
+
+	glBindVertexArray(context->initialShader.vao);
+	glBindBuffer(GL_ARRAY_BUFFER, context->vbo);
+	glVertexAttribPointer(context->initialShader.positionLocation, 2, GL_FLOAT, GL_FALSE, 0, NULL);
+	glBindVertexArray(context->finalShader.vao);
+	glBindBuffer(GL_ARRAY_BUFFER, context->vbo);
+	glVertexAttribPointer(context->finalShader.positionLocation, 2, GL_FLOAT, GL_FALSE, 0, NULL);
+	glBindVertexArray(0);
+
 	glDeleteFramebuffers(1, &context->finalShader.fbo);
 	glDeleteTextures(1, &context->finalShader.tex);
 	context->finalShader.fbo = 0;
@@ -296,6 +305,7 @@ void _drawShader(struct mGLES2Context* context, struct mGLES2Shader* shader) {
 			break;
 		}
 	}
+	glEnableVertexAttribArray(shader->positionLocation);
 	glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
 	glBindTexture(GL_TEXTURE_2D, shader->tex);
 }
@@ -426,10 +436,6 @@ void mGLES2ShaderInit(struct mGLES2Shader* shader, const char* vs, const char* f
 	}
 
 	glGenVertexArrays(1, &shader->vao);
-	glBindVertexArray(shader->vao);
-	glVertexAttribPointer(shader->positionLocation, 2, GL_FLOAT, GL_FALSE, 0, NULL);
-	glEnableVertexAttribArray(shader->positionLocation);
-	glBindVertexArray(0);
 
 	glBindFramebuffer(GL_FRAMEBUFFER, 0);
 }
@@ -458,6 +464,8 @@ void mGLES2ShaderAttach(struct mGLES2Context* context, struct mGLES2Shader* shad
 
 		glBindVertexArray(context->shaders[i].vao);
 		glBindBuffer(GL_ARRAY_BUFFER, context->vbo);
+		glVertexAttribPointer(context->shaders[i].positionLocation, 2, GL_FLOAT, GL_FALSE, 0, NULL);
+		glEnableVertexAttribArray(context->shaders[i].positionLocation);
 	}
 	glBindVertexArray(0);
 	glBindFramebuffer(GL_FRAMEBUFFER, 0);