From 8902efa52d805ac87544d0fb990273538e7b668e Mon Sep 17 00:00:00 2001
From: Stephan Unverwerth <s.unverwerth@serenityos.org>
Date: Wed, 11 Aug 2021 21:18:01 +0200
Subject: [PATCH] LibGL: Implement "clamp" wrap mode

---
 Userland/Libraries/LibGL/GL/gl.h           |  5 ++++-
 Userland/Libraries/LibGL/Tex/Sampler2D.cpp | 19 +++++++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/Userland/Libraries/LibGL/GL/gl.h b/Userland/Libraries/LibGL/GL/gl.h
index 5b632506160..93609a8b271 100644
--- a/Userland/Libraries/LibGL/GL/gl.h
+++ b/Userland/Libraries/LibGL/GL/gl.h
@@ -199,7 +199,10 @@ extern "C" {
 #define GL_NEAREST 0x2600
 #define GL_LINEAR 0x2601
 #define GL_NEAREST_MIPMAP_LINEAR 0x2602
-#define GL_REPEAT 0x2603
+#define GL_CLAMP 0x2900
+#define GL_REPEAT 0x2901
+#define GL_CLAMP_TO_BORDER 0x812D
+#define GL_CLAMP_TO_EDGE 0x812F
 
 // OpenGL State & GLGet
 #define GL_MODELVIEW_MATRIX 0x0BA6
diff --git a/Userland/Libraries/LibGL/Tex/Sampler2D.cpp b/Userland/Libraries/LibGL/Tex/Sampler2D.cpp
index e88babfae67..f2d1aeeb1f5 100644
--- a/Userland/Libraries/LibGL/Tex/Sampler2D.cpp
+++ b/Userland/Libraries/LibGL/Tex/Sampler2D.cpp
@@ -16,6 +16,11 @@ static constexpr float wrap_repeat(float value)
     return value - floorf(value);
 }
 
+static constexpr float wrap_clamp(float value)
+{
+    return clamp(value, 0.0f, 1.0f);
+}
+
 FloatVector4 Sampler2D::sample(FloatVector2 const& uv) const
 {
     // FIXME: Calculate the correct mipmap level here, need to receive uv derivatives for that
@@ -31,6 +36,13 @@ FloatVector4 Sampler2D::sample(FloatVector2 const& uv) const
         x = wrap_repeat(x);
         break;
 
+    // FIXME: These clamp modes actually have slightly different behaviour
+    case GL_CLAMP:
+    case GL_CLAMP_TO_BORDER:
+    case GL_CLAMP_TO_EDGE:
+        x = wrap_clamp(x);
+        break;
+
     default:
         VERIFY_NOT_REACHED();
     }
@@ -40,6 +52,13 @@ FloatVector4 Sampler2D::sample(FloatVector2 const& uv) const
         y = wrap_repeat(y);
         break;
 
+    // FIXME: These clamp modes actually have slightly different behaviour
+    case GL_CLAMP:
+    case GL_CLAMP_TO_BORDER:
+    case GL_CLAMP_TO_EDGE:
+        y = wrap_clamp(y);
+        break;
+
     default:
         VERIFY_NOT_REACHED();
     }