From a62211d3a14a5f763b19a6a6bfc2031a33e04d5e Mon Sep 17 00:00:00 2001
From: Sebastian Snoer <23051740+Seba244c@users.noreply.github.com>
Date: Sat, 24 Feb 2024 20:12:49 +0100
Subject: [PATCH] fix: update UV coordinates in GLSL shader to correctly sample
 texture (#44)

---
 .../opengl/components/SpriteRenderer.java     |  6 ++++-
 .../opengl/renderer/GL2DRenderer.java         |  4 +--
 .../opengl/renderer/GLSpriteRenderer.java     | 25 +++++++++++++++++++
 .../spellbook/shaders/SpellbookSprite.glsl    |  2 +-
 4 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/spellbook/src/main/java/dk/sebsa/spellbook/graphics/opengl/components/SpriteRenderer.java b/spellbook/src/main/java/dk/sebsa/spellbook/graphics/opengl/components/SpriteRenderer.java
index da44beb..a55f2c1 100644
--- a/spellbook/src/main/java/dk/sebsa/spellbook/graphics/opengl/components/SpriteRenderer.java
+++ b/spellbook/src/main/java/dk/sebsa/spellbook/graphics/opengl/components/SpriteRenderer.java
@@ -75,7 +75,9 @@ public SpriteRenderer(Identifier spritesheet, String sprite) {
      * @param renderer Batchrenderer to render with
      */
     public void draw(GLSpriteRenderer renderer) {
+        if(sprite==null) onEnable();
         Rect uvRect = sprite.getUV();
+
         Vector3f pos = entity.transform.getGlobalPosition();
         Vector2f size = new Vector2f(sprite.getOffset().width, sprite.getOffset().height);
 
@@ -86,6 +88,7 @@ public void draw(GLSpriteRenderer renderer) {
     }
 
     public void onEnable() {
+        if(sprite != null) return;
         if(spriteSheetSprite != null) { // If this sprite is set using a spritesheet
             this.spriteSheet = (SpriteSheet) AssetManager.getAssetS(identifier);
             this.sprite = spriteSheet.spr(spriteSheetSprite);
@@ -100,7 +103,8 @@ public void onEnable() {
 
     @Override
     public void render() {
-        Spellbook.FRAME_DATA.addRenderSprite(this);
+        if(sprite != null)
+            Spellbook.FRAME_DATA.addRenderSprite(this);
     }
 
     @Override
diff --git a/spellbook/src/main/java/dk/sebsa/spellbook/graphics/opengl/renderer/GL2DRenderer.java b/spellbook/src/main/java/dk/sebsa/spellbook/graphics/opengl/renderer/GL2DRenderer.java
index 119a025..698650b 100644
--- a/spellbook/src/main/java/dk/sebsa/spellbook/graphics/opengl/renderer/GL2DRenderer.java
+++ b/spellbook/src/main/java/dk/sebsa/spellbook/graphics/opengl/renderer/GL2DRenderer.java
@@ -25,10 +25,10 @@
 public class GL2DRenderer {
     @Getter
     protected final GLSLShaderProgram shader;
+    protected final FloatBuffer vertices;
     private final VBO vbo;
-    private final FloatBuffer vertices;
     private final VAO vao;
-    private int numVertices = 0;
+    protected int numVertices = 0;
 
     /**
      * A GLBatchRenderer using the provided shader
diff --git a/spellbook/src/main/java/dk/sebsa/spellbook/graphics/opengl/renderer/GLSpriteRenderer.java b/spellbook/src/main/java/dk/sebsa/spellbook/graphics/opengl/renderer/GLSpriteRenderer.java
index 36176c5..9dac295 100644
--- a/spellbook/src/main/java/dk/sebsa/spellbook/graphics/opengl/renderer/GLSpriteRenderer.java
+++ b/spellbook/src/main/java/dk/sebsa/spellbook/graphics/opengl/renderer/GLSpriteRenderer.java
@@ -2,6 +2,7 @@
 
 import dk.sebsa.spellbook.asset.Identifier;
 import dk.sebsa.spellbook.ecs.Camera;
+import dk.sebsa.spellbook.math.Rect;
 import org.joml.Matrix4f;
 
 /**
@@ -21,4 +22,28 @@ public void begin(Matrix4f mProj) {
         super.begin(mProj);
         shader.setUniform("mView", Camera.activeCamera.getViewMatrix());
     }
+
+    @Override
+    public void drawQuad(Rect rect, Rect uv) {
+        if (vertices.remaining() < Float.BYTES * 4) flush();
+        float x1 = rect.x;
+        float x2 = rect.x + rect.width;
+        float y1 = rect.y;
+        float y2 = rect.y + rect.height;
+
+        float s1 = uv.x;
+        float s2 = uv.x + uv.width;
+        float t2 = uv.y;
+        float t1 = uv.y + uv.height;
+
+        vertices.put(x1).put(y2).put(s1).put(t2);
+        vertices.put(x2).put(y2).put(s2).put(t2);
+        vertices.put(x2).put(y1).put(s2).put(t1);
+
+        vertices.put(x2).put(y1).put(s2).put(t1);
+        vertices.put(x1).put(y1).put(s1).put(t1);
+        vertices.put(x1).put(y2).put(s1).put(t2);
+
+        numVertices += 6;
+    }
 }
diff --git a/spellbook/src/main/resources/spellbook/shaders/SpellbookSprite.glsl b/spellbook/src/main/resources/spellbook/shaders/SpellbookSprite.glsl
index a06272d..e434e97 100644
--- a/spellbook/src/main/resources/spellbook/shaders/SpellbookSprite.glsl
+++ b/spellbook/src/main/resources/spellbook/shaders/SpellbookSprite.glsl
@@ -27,5 +27,5 @@ uniform sampler2D texSampler;
 uniform vec4 matColor;
 
 void main() {
-    fragColor = matColor * texture(texSampler, vec2(uvCoords.x, 1.0-uvCoords.y));
+    fragColor = matColor * texture(texSampler, vec2(uvCoords.x, uvCoords.y));
 }
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