Texture API improvements

1. Selective mipmapping
2. Manual mipmap generation (actually produced better results at least
for alpha-tested foliage)

src/k3.c

@@ -17,6 +17,8 @@
 
 #include"ssort.h"
 
+#include<stb_image_resize.h>
+
 #define RAST_DIFF 0
 #define RAST_NORM 1
 #define RAST_DISP 2
@@ -495,6 +497,20 @@ struct k3Tex *k3TexCreate(enum k3TexType type) {
 	return ret;
 }
 
+int k3TexSetParameter(struct k3Tex *tex, enum k3TexParam param, void *value) {
+	switch(param) {
+	case k3_TEX_SET_MIPMAPPING_DISABLED:
+		tex->mipmapForceDisabled = *(bool*) value;
+		return 0;
+		
+	case k3_TEX_SET_MIPMAP_ALPHA:
+		tex->mipmapAlphaMode = *(int*) value;
+		return 0;
+	}
+	
+	return 1;
+}
+
 void k3TexUpdate(struct k3Tex *tex, enum k3TexType type, int index, uint16_t width, uint16_t height, void *data) {
 	GLenum target = tex->cubemap ? GL_TEXTURE_CUBE_MAP : GL_TEXTURE_2D;
 	
@@ -518,22 +534,28 @@ void k3TexUpdate(struct k3Tex *tex, enum k3TexType type, int index, uint16_t wid
 	GLint internalFmt, externalFmt, intype;
 	int linearFilter, mipmap;
 	int compressed = 0;
+	int channels;
+	bool gamma;
 	
 	switch(type) {
 		case k3_RAWCOLOR:
 			internalFmt = GLAD_GL_ARB_texture_float ? GL_RGBA32F_ARB : GL_RGB10_A2;
 			externalFmt = GL_RGBA;
+			channels = 4;
 			intype = GL_UNSIGNED_BYTE;
 			linearFilter = 1;
-			mipmap = 1;
+			mipmap = 0;
+			gamma = false;
 			break;
 		case k3_NORMAL:
 			compressed = TextureCompressionEnabled;
 			internalFmt = compressed ? TextureCompressionRGBA : GL_RGBA;
 			externalFmt = GL_RGBA;
+			channels = 4;
 			intype = GL_UNSIGNED_BYTE;
 			linearFilter = 1;
 			mipmap = 1;
+			gamma = false;
 			break;
 		case k3_DIFFUSE:
 		case k3_EMISSION:
@@ -542,39 +564,47 @@ void k3TexUpdate(struct k3Tex *tex, enum k3TexType type, int index, uint16_t wid
 				?	(GLAD_GL_EXT_texture_sRGB ? TextureCompressionSRGBA : TextureCompressionRGBA)
 				:	(GLAD_GL_EXT_texture_sRGB ? GL_SRGB8_ALPHA8_EXT : GL_RGBA8);
 			externalFmt = GL_RGBA;
+			channels = 4;
 			intype = GL_UNSIGNED_BYTE;
 			linearFilter = 1;
 			mipmap = 1;
+			gamma = true;
 			break;
 		case k3_DISPLACEMENT:
 		case k3_ROUGHNESS:
 			internalFmt = !k3IsCore ? GL_LUMINANCE8 : GL_RED;
 			externalFmt = GL_RED;
+			channels = 1;
 			intype = GL_UNSIGNED_BYTE;
 			linearFilter = 1;
 			mipmap = 1;
+			gamma = false;
 			break;
 		case k3_ALPHA:
 			internalFmt = !k3IsCore ? GL_ALPHA8 : GL_RED;
 			externalFmt = !k3IsCore ? GL_ALPHA : GL_RED;
+			channels = 1;
 			intype = GL_UNSIGNED_BYTE;
 			linearFilter = 1;
 			mipmap = 1;
+			gamma = false;
 			break;
 		case k3_DEPTH:
-			internalFmt = GL_DEPTH_COMPONENT32F;
+			internalFmt = GL_DEPTH_COMPONENT24;
 			externalFmt = GL_DEPTH_COMPONENT;
 			intype = GL_UNSIGNED_INT;
+			channels = 4;
 			if(!k3IsCore) glTexParameteri(target, GL_DEPTH_TEXTURE_MODE, GL_LUMINANCE);
 			linearFilter = 1;
 			mipmap = 0;
+			gamma = false;
 			break;
 		default:
 			abort();
 			break;
 	}
 	
-	if(!MipmappingEnabled) {
+	if(!MipmappingEnabled || tex->mipmapForceDisabled) {
 		mipmap = 0;
 	}
 	
@@ -587,10 +617,6 @@ void k3TexUpdate(struct k3Tex *tex, enum k3TexType type, int index, uint16_t wid
 			glTexParameteri(target, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 			glTexParameteri(target, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 			glTexParameteri(target, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
-		} else {
-			if(!k3IsCore && mipmap) {
-				glTexParameteri(target, GL_GENERATE_MIPMAP, GL_TRUE);
-			}
 		}
 		
 		if(type == k3_DEPTH) {
@@ -623,23 +649,6 @@ void k3TexUpdate(struct k3Tex *tex, enum k3TexType type, int index, uint16_t wid
 		k3Log(k3_WARN, "Non-zero index passed for non-cubemap texture");
 	}
 	
-	if(compressed && TextureOfflineCompressor) {
-		k3Log(k3_DEBUG, "Compressing texture...");
-		
-		size_t len;
-		data = TextureOfflineCompressor(data, width, height, externalFmt, intype, &len);
-		
-		glCompressedTexImage2D(target, 0, internalFmt, width, height, 0, len, data);
-		
-		free(data);
-	} else {
-		glTexImage2D(target, 0, internalFmt, width, height, 0, externalFmt, intype, data);
-	}
-	
-	if(!tex->cubemap && k3IsCore && mipmap) {
-		glGenerateMipmap(target);
-	}
-	
 	tex->szX = width;
 	tex->szY = height;
 	tex->szZ = 0;
@@ -647,6 +656,65 @@ void k3TexUpdate(struct k3Tex *tex, enum k3TexType type, int index, uint16_t wid
 	tex->glInternalFormat = internalFmt;
 	tex->glExternalFormat = externalFmt;
 	tex->glInType = intype;
+	
+	if(data) {
+		char *resized = malloc(width * height * channels);
+		memcpy(resized, data, width * height * channels);
+		
+		size_t level;
+		for(level = 0;; level++) {
+			if(compressed && TextureOfflineCompressor) {
+				k3Log(k3_DEBUG, "Compressing level %i...", level);
+				
+				size_t len;
+				void *compressedData = TextureOfflineCompressor(data, width, height, externalFmt, intype, &len);
+				
+				glCompressedTexImage2D(target, level, internalFmt, width, height, 0, len, compressedData);
+				
+				free(compressedData);
+			} else {
+				glTexImage2D(target, level, internalFmt, width, height, 0, externalFmt, intype, data);
+			}
+			
+			if(!mipmap || tex->cubemap || (width <= 1 && height <= 1)) {
+				break;
+			}
+			
+			size_t resizedWidth = width >> 1;
+			if(resizedWidth == 0) {
+				resizedWidth = 1;
+			}
+			
+			size_t resizedHeight = height >> 1;
+			if(resizedHeight == 0) {
+				resizedHeight = 1;
+			}
+			
+			stbir_resize_uint8_generic(data, width, height, 0, resized, resizedWidth, resizedHeight, 0, channels, channels == 4 ? 3 : STBIR_ALPHA_CHANNEL_NONE, 0, STBIR_EDGE_CLAMP, STBIR_FILTER_BOX, gamma ? STBIR_COLORSPACE_SRGB : STBIR_COLORSPACE_LINEAR, NULL);
+			
+			data = resized;
+			width = resizedWidth;
+			height = resizedHeight;
+		}
+		
+		glTexParameteri(target, GL_TEXTURE_BASE_LEVEL, 0);
+		glTexParameteri(target, GL_TEXTURE_MAX_LEVEL, level);
+		
+		free(resized);
+	} else {
+		glTexImage2D(target, 0, internalFmt, width, height, 0, externalFmt, intype, NULL);
+	}
+}
+void k3TexUpdateSub(struct k3Tex *this, int index, uint16_t x, uint16_t y, uint16_t width, uint16_t height, void *data) {
+	GLenum target = GL_TEXTURE_2D;
+	if(this->cubemap) {
+		target = GL_TEXTURE_CUBE_MAP_POSITIVE_X + index;
+	} else if(index) {
+		k3Log(k3_WARN, "Non-zero index passed for non-cubemap texture");
+	}
+	
+	glBindTexture(target, this->tex);
+	glTexSubImage2D(target, index, x, y, width, height, this->glExternalFormat, this->glInType, data);
 }
 uint32_t k3TexSzX(struct k3Tex *this) {
 	return this->szX;

src/k3.h

@@ -22,9 +22,18 @@ enum k3TexType {
 	k3_RAWCOLOR,
 };
 
+enum k3TexParam {
+	k3_TEX_SET_MIPMAP_ALPHA,
+	k3_TEX_SET_MIPMAPPING_DISABLED,
+};
+#define k3_PARAM_STANDARD 0
+#define k3_PARAM_MAX_DOWNSAMPLE 1
+
 struct k3Tex;
 struct k3Tex *k3TexCreate(enum k3TexType type);
+int k3TexSetParameter(struct k3Tex*, enum k3TexParam, void*);
 void k3TexUpdate(struct k3Tex*, enum k3TexType type, int index, uint16_t width, uint16_t height, void *data);
+void k3TexUpdateSub(struct k3Tex*, int index, uint16_t x, uint16_t y, uint16_t width, uint16_t height, void *data);
 uint32_t k3TexSzX(struct k3Tex*);
 uint32_t k3TexSzY(struct k3Tex*);
 uint32_t k3TexSzZ(struct k3Tex*);

src/k3_internal.h

@@ -28,10 +28,8 @@ struct k3Tex {
 	GLuint glInType;
 	bool mipmap;
 	
-	// Asynchronous decoding
+	bool mipmapForceDisabled;
-	uint8_t deferredRemaining;
+	int mipmapAlphaMode;
-	uint8_t *deferredData[6];
-	struct k3Tex *deferredNext;
 };
 
 struct k3Storage {

src/k3font.c

@@ -48,6 +48,9 @@ int k3FontLoad(struct k3Font *this, const char *fn) {
 	this->atlasSize = k3TexSzMax() / 4;
 	this->atlas = k3TexCreate(k3_ALPHA);
 	this->atlasCPU = malloc(this->atlasSize * this->atlasSize);
+	
+	k3TexSetParameter(this->atlas, k3_TEX_SET_MIPMAPPING_DISABLED, &(bool) {true});
+	
 	k3TexUpdate(this->atlas, k3_ALPHA, 0, this->atlasSize, this->atlasSize, NULL);
 	
 	this->fontPixelSize = this->atlasSize / 16;