From d03acd3b6c6d958ee6a1d30754b946929a1db7c7 Mon Sep 17 00:00:00 2001
From: baldurk <baldurk@baldurk.org>
Date: Wed, 29 Jul 2020 15:17:45 +0100
Subject: [PATCH] Test reading instanced data via client memory pointers in GL

---
 util/test/demos/gl/gl_vao_0.cpp | 33 +++++++++++++++++++++++++++++++--
 util/test/tests/GL/GL_VAO_0.py  | 21 +++++++++++++++++++++
 2 files changed, 52 insertions(+), 2 deletions(-)

diff --git a/util/test/demos/gl/gl_vao_0.cpp b/util/test/demos/gl/gl_vao_0.cpp
index 7973359b2..010e4f3fc 100644
--- a/util/test/demos/gl/gl_vao_0.cpp
+++ b/util/test/demos/gl/gl_vao_0.cpp
@@ -26,7 +26,8 @@
 
 RD_TEST(GL_VAO_0, OpenGLGraphicsTest)
 {
-  static constexpr const char *Description = "Uses VAO 0 (i.e. never binds a VAO)";
+  static constexpr const char *Description =
+      "Uses VAO 0 (i.e. never binds a VAO) as well as testing client memory pointer behaviour.";
 
   std::string common = R"EOSHADER(
 
@@ -49,9 +50,11 @@ layout(location = 2) in vec2 UV;
 
 out v2f vertOut;
 
+uniform vec4 instance_xform;
+
 void main()
 {
-	vertOut.pos = vec4(Position.xyz, 1);
+	vertOut.pos = vec4(Position.x + float(gl_InstanceID % 4), Position.y + float(gl_InstanceID / 4), Position.z, 1) * vec4(instance_xform.xy, 1, 1);
 	gl_Position = vertOut.pos;
 	vertOut.col = Color;
 	vertOut.uv = vec4(UV.xy, 0, 1);
@@ -102,8 +105,14 @@ void main()
 
     GLuint program = MakeProgram(common + vertex, common + pixel);
 
+    GLint loc = glGetUniformLocation(program, "instance_xform");
+
+    glEnable(GL_SCISSOR_TEST);
+
     while(Running())
     {
+      glScissor(0, 0, GLsizei(screenWidth), GLsizei(screenHeight));
+
       float col[] = {0.2f, 0.2f, 0.2f, 1.0f};
       glClearBufferfv(GL_COLOR, 0, col);
 
@@ -116,6 +125,8 @@ void main()
 
       glUseProgram(program);
 
+      glUniform4f(loc, 1.0f, 1.0f, 0.0f, 0.0f);
+
       // use both buffers
       glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ib);
       glBindBuffer(GL_ARRAY_BUFFER, vb);
@@ -150,6 +161,24 @@ void main()
       glViewport((screenWidth * 3) / 4, 0, GLsizei(screenWidth) / 4, GLsizei(screenHeight));
       glDrawElements(GL_TRIANGLES, 3, GL_UNSIGNED_INT, idxs);
 
+      // draw with instance data that requires more data than a non-instanced stream would need
+      glViewport(0, 0, GLsizei(screenWidth) / 2, GLsizei(screenHeight) / 2);
+      glScissor(0, 0, GLsizei(screenWidth) / 2, GLsizei(screenHeight) / 2);
+      glClearBufferfv(GL_COLOR, 0, col);
+
+      Vec4f instcols[20] = {};
+      for(size_t i = 4; i < ARRAY_COUNT(instcols); i++)
+        instcols[i].z = 0.5f * (i - 3);
+
+      glUniform4f(loc, 0.25f, 0.25f, 0.0f, 0.0f);
+
+      glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, sizeof(Vec4f), instcols);
+      glVertexAttribDivisor(1, 1);
+
+      glDrawElementsInstancedBaseInstance(GL_TRIANGLES, 3, GL_UNSIGNED_INT, idxs, 16, 4);
+
+      glVertexAttribDivisor(1, 0);
+
       Present();
     }
 
diff --git a/util/test/tests/GL/GL_VAO_0.py b/util/test/tests/GL/GL_VAO_0.py
index 5bfa5c243..45223e3bd 100644
--- a/util/test/tests/GL/GL_VAO_0.py
+++ b/util/test/tests/GL/GL_VAO_0.py
@@ -52,3 +52,24 @@ class GL_VAO_0(rdtest.TestCase):
 
             draw = draw.next
 
+        draw = self.find_draw("Instanced")
+
+        self.check(draw is not None)
+
+        self.controller.SetFrameEvent(draw.eventId, False)
+
+        # Each instance should have color output of 0.5 * instance in blue
+        for i in range(0, draw.numInstances):
+            postvs_data = self.get_postvs(draw, rd.MeshDataStage.VSOut, 0, draw.numIndices, i)
+
+            postvs_ref = {
+                0: {
+                    'vtx': 0,
+                    'idx': 0,
+                    'v2f_block.col': [0.0, 0.0, 0.5*(i+1), 0.0],
+                },
+            }
+
+            self.check_mesh_data(postvs_ref, postvs_data)
+
+            rdtest.log.success('Instance {} is OK'.format(i))