From 6d1ddad428f87798e014869646b42fcee34249e3 Mon Sep 17 00:00:00 2001
From: Redacted <william@stepmail.co>
Date: Thu, 6 Feb 2025 10:26:34 -0500
Subject: [PATCH] Add a way to query the max texture size.

---
 include/JGL/types/RenderTarget.h |  5 +++--
 include/JGL/types/Texture.h      |  5 ++++-
 src/types/RenderTarget.cpp       |  4 ++++
 src/types/Texture.cpp            | 18 ++++++++++++++++++
 4 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/include/JGL/types/RenderTarget.h b/include/JGL/types/RenderTarget.h
index 25503ef..e012cbd 100644
--- a/include/JGL/types/RenderTarget.h
+++ b/include/JGL/types/RenderTarget.h
@@ -91,10 +91,11 @@ public:
     /// @returns The color that should be used to clear this Render Target.
     [[nodiscard]] Color4 GetClearColor() const;
 
-
     /// @returns The color information for this Render Target.
-    /// @note Both the CPU & GPU cannot do anything while this takes place. It's very slow.
+    /// @note The CPU thread this is called from & the GPU cannot do anything while this takes place. It's very slow.
     [[nodiscard]] std::vector<GLfloat> GetPixels() const;
+
+    [[nodiscard]] static Vector2i MaximimSize();
 public:
     /// Create a Render Target from a Render Target that already exists.
     /** @note Render Targets that are copies of another will copy the Texture.
diff --git a/include/JGL/types/Texture.h b/include/JGL/types/Texture.h
index 183efc7..0948034 100644
--- a/include/JGL/types/Texture.h
+++ b/include/JGL/types/Texture.h
@@ -27,7 +27,6 @@ namespace JGL {
     class Texture;
 }
 
-/// TODO handle the case of a texture being loaded that exceeds the max texture size.
 /// Represents texture data loaded on the GPU. Contains a handle that can be passed to OpenGL draw calls.
 class JGL::Texture {
 protected:
@@ -40,6 +39,7 @@ protected:
     void load(const unsigned char* pixels);
     std::vector<unsigned char> png(const std::filesystem::path& file);
     std::vector<unsigned char> bmp(const std::filesystem::path& file);
+    [[nodiscard]] bool SizeExceedsMaximum(const Vector2i& size);
 public:
     /// @returns A handle used to identify this texture.
     [[nodiscard]] unsigned int GetHandle() const;
@@ -56,6 +56,9 @@ public:
     /// @returns The raw pixels this texture is made up of.
     /// @note This will read-back from the GPU. Slow.
     [[nodiscard]] std::vector<Color4> GetPixelData() const;
+    /// @returns The biggest size for a texture on this system.
+    /// @note on modern systems this is *usually* ridiculous.
+    [[nodiscard]] static Vector2i MaximumSize();
 public:
     /// Load a texture from a file,
     explicit Texture(const std::filesystem::path& file, FilteringMode filtering_mode = FilteringMode::BILINEAR, WrappingMode wrapping_mode = WrappingMode::CLAMP_TO_EDGE, bool invert_y = true);
diff --git a/src/types/RenderTarget.cpp b/src/types/RenderTarget.cpp
index 86a18df..cad7803 100644
--- a/src/types/RenderTarget.cpp
+++ b/src/types/RenderTarget.cpp
@@ -381,3 +381,7 @@ JGL::RenderTarget::RenderTarget(const JGL::RenderTarget& rhs) {
 
     operator delete(this_render_target);
 }
+
+Vector2i JGL::RenderTarget::MaximimSize() {
+    return Texture::MaximumSize();
+}
diff --git a/src/types/Texture.cpp b/src/types/Texture.cpp
index 6269bc6..0b2e161 100644
--- a/src/types/Texture.cpp
+++ b/src/types/Texture.cpp
@@ -99,6 +99,8 @@ std::vector<unsigned char> Texture::bmp(const std::filesystem::path& file) {
 }
 
 Texture::Texture(const Vector2i& size) : invert_y(true), format(ColorFormat::RGBA), size(size), filtering_mode(FilteringMode::NEAREST), wrapping_mode(WrappingMode::CLAMP_TO_EDGE) {
+    if (SizeExceedsMaximum(size))
+        Logger::Error("Creating a texture where the size is bigger than the maximum for this system.");
     GLuint previous_texture;
     glGetIntegerv(GL_TEXTURE_BINDING_2D, (GLint*) &previous_texture);
 
@@ -116,6 +118,9 @@ Texture::Texture(const Vector2i& size) : invert_y(true), format(ColorFormat::RGB
 }
 
 void Texture::load(const unsigned char* pixels) {
+    if (SizeExceedsMaximum(size))
+        Logger::Error("Creating a texture where the size is bigger than the maximum for this system.");
+
     GLuint previous_texture;
     glGetIntegerv(GL_TEXTURE_BINDING_2D, (GLint*) &previous_texture);
 
@@ -272,3 +277,16 @@ Texture::Texture(const Texture* textures, const size_t& texture_count) {
         next_x += textures[i].GetDimensions().x;
     }
 }
+
+bool Texture::SizeExceedsMaximum(const Vector2i& s) {
+
+    auto max_size = Texture::MaximumSize();
+    return s.x > max_size.x || s.y > max_size.y;
+}
+
+Vector2i Texture::MaximumSize() {
+    GLint max_size;
+    glGetIntegerv(GL_MAX_TEXTURE_SIZE, &max_size);
+
+    return { max_size, max_size };
+}