SDL: testgles2: Use vertex buffer objects instead of client-side arrays.

From ca22b30e46238d870251ff2dbc68744fd111f4f2 Mon Sep 17 00:00:00 2001
From: "Ryan C. Gordon" <[EMAIL REDACTED]>
Date: Mon, 24 Jan 2022 22:32:58 -0500
Subject: [PATCH] testgles2: Use vertex buffer objects instead of client-side
 arrays.

GLES2 always has them, and they work without hacks on Emscripten, unlike
client-side arrays.

I cleaned it up slightly, but this patch was mostly written by @bing2008.

Fixes #5258.
---
 test/testgles2.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/test/testgles2.c b/test/testgles2.c
index b6180aeaaaa..153ebe49958 100644
--- a/test/testgles2.c
+++ b/test/testgles2.c
@@ -372,6 +372,8 @@ typedef struct shader_data
 
     int angle_x, angle_y, angle_z;
 
+    GLuint position_buffer;
+    GLuint color_buffer;
 } shader_data;
 
 static void
@@ -688,8 +690,18 @@ main(int argc, char *argv[])
         GL_CHECK(ctx.glEnableVertexAttribArray(data->attr_color));
 
         /* Populate attributes for position, color and texture coordinates etc. */
-        GL_CHECK(ctx.glVertexAttribPointer(data->attr_position, 3, GL_FLOAT, GL_FALSE, 0, _vertices));
-        GL_CHECK(ctx.glVertexAttribPointer(data->attr_color, 3, GL_FLOAT, GL_FALSE, 0, _colors));
+
+        GL_CHECK(ctx.glGenBuffers(1, &data->position_buffer));
+        GL_CHECK(ctx.glBindBuffer(GL_ARRAY_BUFFER, data->position_buffer));
+        GL_CHECK(ctx.glBufferData(GL_ARRAY_BUFFER, sizeof(_vertices) * 4, _vertices, GL_STATIC_DRAW));
+        GL_CHECK(ctx.glVertexAttribPointer(data->attr_position, 3, GL_FLOAT, GL_FALSE, 0, 0));
+        GL_CHECK(ctx.glBindBuffer(GL_ARRAY_BUFFER, 0));
+
+        GL_CHECK(ctx.glGenBuffers(1, &data->color_buffer));
+        GL_CHECK(ctx.glBindBuffer(GL_ARRAY_BUFFER, data->color_buffer));
+        GL_CHECK(ctx.glBufferData(GL_ARRAY_BUFFER, sizeof(_colors) * 4, _colors, GL_STATIC_DRAW));
+        GL_CHECK(ctx.glVertexAttribPointer(data->attr_color, 3, GL_FLOAT, GL_FALSE, 0, 0));
+        GL_CHECK(ctx.glBindBuffer(GL_ARRAY_BUFFER, 0));
 
         GL_CHECK(ctx.glEnable(GL_CULL_FACE));
         GL_CHECK(ctx.glEnable(GL_DEPTH_TEST));