initial commit

2026-08-07 14:51:41 -05:00
commit 9251b3a196
604 changed files with 464448 additions and 0 deletions
@@ -0,0 +1,128 @@
+package graphics
+
+import (
+	"fmt"
+	"log"
+
+	"github.com/go-gl/gl/v3.3-core/gl"
+	"github.com/veandco/go-sdl2/sdl"
+)
+
+// CreateTextureFromSurface uploads an SDL surface to an OpenGL texture and returns the texture ID.
+func CreateTextureFromSurface(surface *sdl.Surface) (uint32, error) {
+	if surface == nil {
+		return 0, fmt.Errorf("CreateTextureFromSurface: input surface is nil")
+	}
+
+	var textureID uint32
+	var err error
+
+	surfaceToUpload := surface
+	var convertedSurface *sdl.Surface = nil
+
+	sdlFormatEnum := surface.Format.Format
+	var dataFormat uint32
+	var internalFormat int32 = gl.RGBA8
+
+	if sdlFormatEnum == sdl.PIXELFORMAT_INDEX8 {
+		convertedSurface, err = surface.ConvertFormat(sdl.PIXELFORMAT_ARGB8888, 0)
+		if err != nil {
+			return 0, fmt.Errorf("failed to convert INDEX8 surface to ARGB8888: %w", err)
+		}
+		defer convertedSurface.Free()
+
+		surfaceToUpload = convertedSurface
+		sdlFormatEnum = surfaceToUpload.Format.Format
+	}
+
+	switch sdlFormatEnum {
+	case sdl.PIXELFORMAT_ARGB8888:
+		dataFormat = gl.BGRA
+	case sdl.PIXELFORMAT_ABGR8888:
+		dataFormat = gl.RGBA
+	case sdl.PIXELFORMAT_RGBA8888:
+		dataFormat = gl.RGBA
+	case sdl.PIXELFORMAT_BGRA8888:
+		dataFormat = gl.BGRA
+	default:
+		return 0, fmt.Errorf("unhandled SDL pixel format for OpenGL upload: %s", sdl.GetPixelFormatName(uint(sdlFormatEnum)))
+	}
+
+	for errCode := gl.GetError(); errCode != gl.NO_ERROR; errCode = gl.GetError() {
+		log.Printf("OpenGL error pending before GenTextures: 0x%X", errCode)
+	}
+
+	gl.GenTextures(1, &textureID)
+	if errCode := gl.GetError(); errCode != gl.NO_ERROR {
+		return 0, fmt.Errorf("OpenGL error 0x%X after GenTextures", errCode)
+	}
+	if textureID == 0 {
+		return 0, fmt.Errorf("gl.GenTextures returned textureID 0")
+	}
+
+	gl.BindTexture(gl.TEXTURE_2D, textureID)
+
+	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST)
+	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST)
+	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE)
+	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE)
+
+	gl.PixelStorei(gl.UNPACK_ALIGNMENT, 1)
+
+	expectedPitch := surfaceToUpload.W * int32(surfaceToUpload.Format.BytesPerPixel)
+	if int32(surfaceToUpload.Pitch) != expectedPitch {
+		gl.PixelStorei(gl.UNPACK_ROW_LENGTH, surfaceToUpload.Pitch/int32(surfaceToUpload.Format.BytesPerPixel))
+	} else {
+		gl.PixelStorei(gl.UNPACK_ROW_LENGTH, 0)
+	}
+
+	gl.TexImage2D(
+		gl.TEXTURE_2D,
+		0,
+		internalFormat,
+		surfaceToUpload.W,
+		surfaceToUpload.H,
+		0,
+		dataFormat,
+		gl.UNSIGNED_BYTE,
+		gl.Ptr(surfaceToUpload.Pixels()),
+	)
+
+	gl.PixelStorei(gl.UNPACK_ALIGNMENT, 4)
+	gl.PixelStorei(gl.UNPACK_ROW_LENGTH, 0)
+
+	if glErr := gl.GetError(); glErr != gl.NO_ERROR {
+		gl.DeleteTextures(1, &textureID)
+		return 0, fmt.Errorf("OpenGL error 0x%X after TexImage2D", glErr)
+	}
+
+	gl.BindTexture(gl.TEXTURE_2D, 0)
+	return textureID, nil
+}
+
+// CheckGLError queries OpenGL for errors and returns the first one found.
+func CheckGLError() error {
+	errCode := gl.GetError()
+	if errCode == gl.NO_ERROR {
+		return nil
+	}
+
+	switch errCode {
+	case gl.INVALID_ENUM:
+		return fmt.Errorf("INVALID_ENUM")
+	case gl.INVALID_VALUE:
+		return fmt.Errorf("INVALID_VALUE")
+	case gl.INVALID_OPERATION:
+		return fmt.Errorf("INVALID_OPERATION")
+	case gl.STACK_OVERFLOW:
+		return fmt.Errorf("STACK_OVERFLOW")
+	case gl.STACK_UNDERFLOW:
+		return fmt.Errorf("STACK_UNDERFLOW")
+	case gl.OUT_OF_MEMORY:
+		return fmt.Errorf("OUT_OF_MEMORY")
+	case gl.INVALID_FRAMEBUFFER_OPERATION:
+		return fmt.Errorf("INVALID_FRAMEBUFFER_OPERATION")
+	default:
+		return fmt.Errorf("Unknown GL error: 0x%X", errCode)
+	}
+}