skybox: added moon and stars

res/shaders/main.glslv

@@ -39,6 +39,7 @@ void main(){
 	skyLightColor.g *= 0.9;
 	skyLightColor.b *= 0.8;
 	skyLightColor = min(vec3(1.0), skyLightColor*SKY_LIGHT_MUL);
+    skyLightColor = max(vec3(0.1, 0.11, 0.14), skyLightColor);
 	
 	a_color.rgb = max(a_color.rgb, skyLightColor.rgb*decomp_light.a);
 	a_distance = length(u_view * u_model * vec4(pos3d.x, pos3d.y*0.2, pos3d.z, 0.0));

res/shaders/skybox_gen.glslf

@@ -277,7 +277,7 @@ void main() {
         MIE_BETA,                       // Mie scattering coefficient
         ABSORPTION_BETA,                // Absorbtion coefficient
         AMBIENT_BETA,					// ambient scattering, turned off for now. This causes the air to glow a bit when no light reaches it
-        G*fog,                          	// Mie preferred scattering direction
+        G*fog*0.7,                          	// Mie preferred scattering direction
         HEIGHT_RAY,                     // Rayleigh scale height
         HEIGHT_MIE*u_mie*u_mie,                     // Mie scale height
         HEIGHT_ABSORPTION,				// the height at which the most absorption happens

src/assets/AssetsLoader.cpp

@@ -60,6 +60,8 @@ void AssetsLoader::addDefaults(AssetsLoader& loader, bool allAssets) {
         loader.add(ASSET_SHADER, SHADERS_FOLDER"/skybox_gen", "skybox_gen");
         loader.add(ASSET_TEXTURE, TEXTURES_FOLDER"/gui/menubg.png", "gui/menubg");
         loader.add(ASSET_TEXTURE, TEXTURES_FOLDER"/gui/delete_icon.png", "gui/delete_icon");
+        loader.add(ASSET_TEXTURE, TEXTURES_FOLDER"/misc/moon.png", "misc/moon");
+        loader.add(ASSET_TEXTURE, TEXTURES_FOLDER"/misc/sun.png", "misc/sun");
         loader.add(ASSET_FONT, FONTS_FOLDER"/font", "normal");
     }
     loader.add(ASSET_ATLAS, TEXTURES_FOLDER"/blocks", "blocks");

src/coders/gzip.h

@@ -6,7 +6,15 @@
 
 namespace gzip {
     const unsigned char MAGIC[] = "\x1F\x8B";
+
+    /* Compress bytes array to GZIP format
+     @param src source bytes array
+     @param size length of source bytes array */
     std::vector<ubyte> compress(const ubyte* src, size_t size);
+    
+    /* Decompress bytes array from GZIP 
+     @param src GZIP data
+     @param size length of GZIP data */
     std::vector<ubyte> decompress(const ubyte* src, size_t size);
 }
 

src/coders/png.cpp

@@ -355,7 +355,9 @@ Texture* png::load_texture(std::string filename) {
 		std::cerr << "Could not load texture " << filename << std::endl;
 		return nullptr;
 	}
-	return Texture::from(image.get());
+	auto texture = Texture::from(image.get());
+    texture->setNearestFilter();
+    return texture;
 }
 
 void png::write_image(std::string filename, const ImageData* image) {

src/frontend/WorldRenderer.cpp

@@ -5,13 +5,14 @@
 #include <memory>
 #include <assert.h>
 
-#include "../content/Content.h"
-#include "../graphics/ChunksRenderer.h"
 #include "../window/Window.h"
 #include "../window/Camera.h"
+#include "../content/Content.h"
+#include "../graphics/ChunksRenderer.h"
 #include "../graphics/Mesh.h"
 #include "../graphics/Atlas.h"
 #include "../graphics/Shader.h"
+#include "../graphics/Batch3D.h"
 #include "../graphics/Texture.h"
 #include "../graphics/LineBatch.h"
 #include "../voxels/Chunks.h"
@@ -46,7 +47,8 @@ WorldRenderer::WorldRenderer(Engine* engine, LevelFrontend* frontend)
 	  lineBatch(new LineBatch()),
 	  renderer(new ChunksRenderer(level, 
                 frontend->getContentGfxCache(), 
-                engine->getSettings())) {
+                engine->getSettings())),
+      batch3d(new Batch3D(4096)) {
 
 	auto& settings = engine->getSettings();
 	level->events->listen(EVT_CHUNK_HIDDEN, 
@@ -129,31 +131,24 @@ void WorldRenderer::drawChunks(Chunks* chunks,
 
 
 void WorldRenderer::draw(const GfxContext& pctx, Camera* camera, bool hudVisible){
+    Window::clearDepth();
 	EngineSettings& settings = engine->getSettings();
-	skybox->refresh(level->world->daytime, 
+	skybox->refresh(pctx, level->world->daytime, 1.0f+fog*2.0f, 4);
-					1.0f+fog*2.0f, 4);
 
 	const Content* content = level->content;
 	auto indices = content->getIndices();
 	Assets* assets = engine->getAssets();
 	Atlas* atlas = assets->getAtlas("blocks");
 	Shader* shader = assets->getShader("main");
-	Shader* linesShader = assets->getShader("lines");
 
 	const Viewport& viewport = pctx.getViewport();
 	int displayWidth = viewport.getWidth();
 	int displayHeight = viewport.getHeight();
-	Window::clearDepth();
-	Window::viewport(0, 0, displayWidth, displayHeight);
 
 	// Drawing background sky plane
-	Shader* backShader = assets->getShader("background");
+	skybox->draw(pctx, camera, assets, level->getWorld()->daytime, fog);
-	backShader->use();
-	backShader->uniformMatrix("u_view", camera->getView(false));
-	backShader->uniform1f("u_zoom", camera->zoom*camera->getFov()/(3.141592*0.5f));
-	backShader->uniform1f("u_ar", float(displayWidth)/float(displayHeight));
-	skybox->draw(backShader);
 
+	Shader* linesShader = assets->getShader("lines");
 	{
 		GfxContext ctx = pctx.sub();
 		ctx.depthTest(true);

src/frontend/WorldRenderer.h

@@ -2,6 +2,7 @@
 #define WORLD_RENDERER_CPP
 
 #include <vector>
+#include <memory>
 #include <algorithm>
 #include <GL/glew.h>
 #include <string>
@@ -14,6 +15,7 @@
 
 class Level;
 class Camera;
+class Batch3D;
 class LineBatch;
 class ChunksRenderer;
 class Shader;
@@ -31,6 +33,7 @@ class WorldRenderer {
 	LineBatch* lineBatch;
 	ChunksRenderer* renderer;
 	Skybox* skybox;
+    std::unique_ptr<Batch3D> batch3d;
 	bool drawChunk(size_t index, Camera* camera, Shader* shader, bool culling);
 	void drawChunks(Chunks* chunks, Camera* camera, Shader* shader);
 public:

src/frontend/graphics/Skybox.cpp

@@ -1,19 +1,28 @@
 #include "Skybox.h"
-#include <GL/glew.h>
+
 #include <iostream>
+#include <GL/glew.h>
 #include <glm/glm.hpp>
 
+#include "../../assets/Assets.h"
 #include "../../graphics/Shader.h"
 #include "../../graphics/Mesh.h"
+#include "../../graphics/Batch3D.h"
 #include "../../window/Window.h"
+#include "../../window/Camera.h"
 
 #ifndef M_PI
 #define M_PI 3.141592
 #endif // M_PI
 
-using glm::vec3;
+const int STARS_COUNT = 3000;
+const int STARS_SEED = 632;
 
-Skybox::Skybox(uint size, Shader* shader) : size(size), shader(shader) {
+Skybox::Skybox(uint size, Shader* shader) 
+    : size(size), 
+      shader(shader), 
+      batch3d(new Batch3D(4096)) 
+{
     glGenTextures(1, &cubemap);
     glBindTexture(GL_TEXTURE_CUBE_MAP, cubemap);
     glTexParameterf(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
@@ -31,30 +40,118 @@ Skybox::Skybox(uint size, Shader* shader) : size(size), shader(shader) {
         -1.0f, -1.0f,  1.0f, 1.0f, 1.0f, -1.0f
     };
     vattr attrs[] {2, 0};
-    mesh = new Mesh(vertices, 6, attrs);
+    mesh = std::make_unique<Mesh>(vertices, 6, attrs);
+
+    sprites.push_back(skysprite {
+        "misc/moon",
+        M_PI*0.5f,
+        4.0f,
+        false
+    });
+
+    sprites.push_back(skysprite {
+        "misc/sun",
+        M_PI*1.5f,
+        4.0f,
+        true
+    });
 }
 
 Skybox::~Skybox() {
     glDeleteTextures(1, &cubemap);
     glDeleteFramebuffers(1, &fbo);
-    delete mesh;
 }
 
-void Skybox::draw(Shader* shader) {
+void Skybox::drawBackground(Camera* camera, Assets* assets, int width, int height) {
-    shader->uniform1i("u_cubemap", 1);
+    Shader* backShader = assets->getShader("background");
+    backShader->use();
+	backShader->uniformMatrix("u_view", camera->getView(false));
+	backShader->uniform1f("u_zoom", camera->zoom*camera->getFov()/(M_PI*0.5f));
+	backShader->uniform1f("u_ar", float(width)/float(height));
+    backShader->uniform1i("u_cubemap", 1);
     bind();
     mesh->draw();
     unbind();
 }
 
-void Skybox::refresh(float t, float mie, uint quality) {
+void Skybox::drawStars(Camera* camera, float angle, float opacity) {
+    batch3d->texture(nullptr);
+    random.setSeed(STARS_SEED);
+    for (int i = 0; i < STARS_COUNT; i++) {
+        float rx = (random.randFloat()) - 0.5f;
+        float ry = (random.randFloat()) - 0.5f;
+        float z = (random.randFloat()) - 0.5f;
+        float x = rx * sin(angle) + ry * -cos(angle);
+        float y = rx * cos(angle) + ry * sin(angle);
+
+        float sopacity = random.randFloat();
+        if (y < 0.0f)
+            continue;
+
+        sopacity *= (0.2f+sqrt(cos(angle))*0.5) - 0.05;
+        glm::vec4 tint (1,1,1, sopacity * opacity);
+        batch3d->point(camera->position + glm::vec3(x, y, z), tint);
+    }
+    batch3d->flushPoints();
+}
+
+void Skybox::draw(
+    const GfxContext& pctx, 
+    Camera* camera, 
+    Assets* assets, 
+    float daytime,
+    float fog) 
+{
+    const Viewport& viewport = pctx.getViewport();
+    int width = viewport.getWidth();
+	int height = viewport.getHeight();
+
+    drawBackground(camera, assets, width, height);
+
+    GfxContext ctx = pctx.sub();
+    ctx.blendMode(blendmode::addition);
+
+    Shader* shader = assets->getShader("ui3d");
+    shader->use();
+    shader->uniformMatrix("u_projview", camera->getProjView());
+    shader->uniformMatrix("u_apply", glm::mat4(1.0f));
+    batch3d->begin();
+
+    float angle = daytime * M_PI * 2;
+    float opacity = glm::pow(1.0f-fog, 7.0f);
+    
+    for (auto& sprite : sprites) {
+        batch3d->texture(assets->getTexture(sprite.texture));
+
+        float sangle = daytime * M_PI*2 + sprite.phase;
+        float distance = sprite.distance;
+
+        glm::vec3 pos(-cos(sangle)*distance, sin(sangle)*distance, 0);
+        glm::vec3 up(-sin(-sangle), cos(-sangle), 0.0f);
+        glm::vec4 tint (1,1,1, opacity);
+        if (!sprite.emissive) {
+            tint *= 0.6f+cos(angle)*0.4;
+        }
+        batch3d->sprite(camera->position+pos, up, 
+                        glm::vec3(0, 0, -1), 1, 1, UVRegion(), tint);
+    }
+
+    drawStars(camera, angle, opacity);
+}
+
+void Skybox::refresh(const GfxContext& pctx, float t, float mie, uint quality) {
+    GfxContext ctx = pctx.sub();
+    ctx.depthMask(false);
+    ctx.depthTest(false);
+
     ready = true;
     glBindFramebuffer(GL_FRAMEBUFFER, fbo);
     glActiveTexture(GL_TEXTURE1);
     glBindTexture(GL_TEXTURE_CUBE_MAP, cubemap);
     shader->use();
-    Window::viewport(0,0, size,size);
+    Window::viewport(0,0, size, size);
-    const vec3 xaxs[] = {
+
+    const glm::vec3 xaxs[] = {
         {0.0f, 0.0f, -1.0f},
         {0.0f, 0.0f, 1.0f},
         {-1.0f, 0.0f, 0.0f},
@@ -63,7 +160,7 @@ void Skybox::refresh(float t, float mie, uint quality) {
         {-1.0f, 0.0f, 0.0f},
         {1.0f, 0.0f, 0.0f},
     };
-    const vec3 yaxs[] = {
+    const glm::vec3 yaxs[] = {
         {0.0f, 1.0f, 0.0f},
         {0.0f, 1.0f, 0.0f},
         {0.0f, 0.0f, -1.0f},
@@ -73,7 +170,7 @@ void Skybox::refresh(float t, float mie, uint quality) {
         {0.0f, 1.0f, 0.0f},
     };
 
-    const vec3 zaxs[] = {
+    const glm::vec3 zaxs[] = {
         {1.0f, 0.0f, 0.0f},
         {-1.0f, 0.0f, 0.0f},
         {0.0f, -1.0f, 0.0f},
@@ -87,7 +184,7 @@ void Skybox::refresh(float t, float mie, uint quality) {
     shader->uniform1i("u_quality", quality);
     shader->uniform1f("u_mie", mie);
     shader->uniform1f("u_fog", mie - 1.0f);
-    shader->uniform3f("u_lightDir", glm::normalize(vec3(sin(t), -cos(t), -0.7f)));
+    shader->uniform3f("u_lightDir", glm::normalize(glm::vec3(sin(t), -cos(t), 0.0f)));
     for (uint face = 0; face < 6; face++) {
         glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_CUBE_MAP_POSITIVE_X + face, cubemap, 0);
         shader->uniform3f("u_xaxis", xaxs[face]);

src/frontend/graphics/Skybox.h

@@ -1,25 +1,52 @@
 #ifndef FRONTEND_GRAPHICS_SKYBOX_H_
 #define FRONTEND_GRAPHICS_SKYBOX_H_
 
+#include <memory>
+#include <string>
+#include <vector>
 #include "../../typedefs.h"
+#include "../../maths/fastmaths.h"
+#include "../../graphics/GfxContext.h"
 
 class Mesh;
 class Shader;
+class Assets;
+class Camera;
+class Batch3D;
+
+struct skysprite {
+    std::string texture;
+    float phase;
+    float distance;
+    bool emissive;
+};
 
 class Skybox {
     uint fbo;
     uint cubemap;
     uint size;
-    Mesh* mesh;
     Shader* shader;
     bool ready = false;
+    FastRandom random;
+
+    std::unique_ptr<Mesh> mesh;
+    std::unique_ptr<Batch3D> batch3d;
+    std::vector<skysprite> sprites;
+
+    void drawStars(Camera* camera, float angle, float opacity);
+    void drawBackground(Camera* camera, Assets* assets, int width, int height);
 public:
     Skybox(uint size, Shader* shader);
     ~Skybox();
 
-    void draw(Shader* shader);
+    void draw(
+        const GfxContext& pctx, 
+        Camera* camera, 
+        Assets* assets, 
+        float daytime,
+        float fog);
 
-    void refresh(float t, float mie, uint quality);
+    void refresh(const GfxContext& pctx, float t, float mie, uint quality);
     void bind() const;
     void unbind() const;
     bool isReady() const {

src/graphics/Batch3D.cpp

@@ -134,9 +134,9 @@ void Batch3D::sprite(vec3 pos, vec3 up, vec3 right, float w, float h, const UVRe
 			uv.u2, uv.v2,
 			r,g,b,a);
 
-	vertex(pos.x - right.x * w - up.x * h,
+	vertex(pos.x - right.x * w + up.x * h,
-			pos.y + right.y * w + up.y * h,
+			pos.y - right.y * w + up.y * h,
-			pos.z - right.z * w - up.z * h,
+			pos.z - right.z * w + up.z * h,
 			uv.u1, uv.v2,
 			r,g,b,a);
 
@@ -146,9 +146,9 @@ void Batch3D::sprite(vec3 pos, vec3 up, vec3 right, float w, float h, const UVRe
 			uv.u1, uv.v1,
 			r,g,b,a);
 
-	vertex(pos.x + right.x * w + up.x * h,
+	vertex(pos.x + right.x * w - up.x * h,
-			pos.y - right.y * w - up.y * h,
+			pos.y + right.y * w - up.y * h,
-			pos.z + right.z * w + up.z * h,
+			pos.z + right.z * w - up.z * h,
 			uv.u2, uv.v1,
 			r,g,b,a);
 
@@ -178,8 +178,18 @@ void Batch3D::blockCube(const vec3 size, const UVRegion(&texfaces)[6], const vec
 	face(coord+vec3(size.x, 0.0f, 0.0f), size.z, size.y, vec3(0, 0, -1), vec3(0, 1, 0), texfaces[1], (shading ? do_tint(0.9f)*tint : tint));
 }
 
+void Batch3D::point(glm::vec3 coord, glm::vec4 tint) {
+    vertex(coord, glm::vec2(), tint.r, tint.g, tint.b, tint.a);
+}
+
 void Batch3D::flush() {
 	mesh->reload(buffer, index / B3D_VERTEX_SIZE);
 	mesh->draw();
 	index = 0;
 }
+
+void Batch3D::flushPoints() {
+    mesh->reload(buffer, index / B3D_VERTEX_SIZE);
+	mesh->draw(GL_POINTS);
+	index = 0;
+}

src/graphics/Batch3D.h

@@ -43,7 +43,9 @@ public:
 	void sprite(glm::vec3 pos, glm::vec3 up, glm::vec3 right, float w, float h, const UVRegion& uv, glm::vec4 tint);
 	void xSprite(float w, float h, const UVRegion& uv, const glm::vec4 tint, bool shading=true);
 	void blockCube(const glm::vec3 size, const UVRegion(&texfaces)[6], const glm::vec4 tint, bool shading=true);
+    void point(glm::vec3 pos, glm::vec4 tint);
 	void flush();
+    void flushPoints();
 };
 
 #endif /* GRAPHICS_BATCH3D_H_ */

src/graphics/GfxContext.cpp

@@ -11,6 +11,9 @@ GfxContext::GfxContext(const GfxContext* parent, Viewport& viewport, Batch2D* g2
 GfxContext::~GfxContext() {
     if (parent == nullptr)
         return;
+    if (depthMask_ != parent->depthMask_) {
+        glDepthMask(parent->depthMask_);
+    }
     if (depthTest_ != parent->depthTest_) {
         if (depthTest_) glDisable(GL_DEPTH_TEST);
         else glEnable(GL_DEPTH_TEST);
@@ -19,6 +22,9 @@ GfxContext::~GfxContext() {
         if (cullFace_) glDisable(GL_CULL_FACE);
         else glEnable(GL_CULL_FACE);
     }
+    if (blendMode_ != parent->blendMode_) {
+        Window::setBlendMode(parent->blendMode_);
+    }
 }
 
 const Viewport& GfxContext::getViewport() const {
@@ -36,11 +42,18 @@ GfxContext GfxContext::sub() const {
     return ctx;
 }
 
+void GfxContext::depthMask(bool flag) {
+    if (depthMask_ == flag)
+        return;
+    depthMask_ = flag;
+    glDepthMask(GL_FALSE + flag);
+}
+
 void GfxContext::depthTest(bool flag) {
     if (depthTest_ == flag)
         return;
     depthTest_ = flag;
-    if (depthTest_) {
+    if (flag) {
         glEnable(GL_DEPTH_TEST);
     } else {
         glDisable(GL_DEPTH_TEST);
@@ -51,9 +64,16 @@ void GfxContext::cullFace(bool flag) {
     if (cullFace_ == flag)
         return;
     cullFace_ = flag;
-    if (cullFace_) {
+    if (flag) {
         glEnable(GL_CULL_FACE);
     } else {
         glDisable(GL_CULL_FACE);
     }
 }
+
+void GfxContext::blendMode(blendmode mode) {
+    if (blendMode_ == mode)
+        return;
+    blendMode_ = mode;
+    Window::setBlendMode(mode);
+}

src/graphics/GfxContext.h

@@ -3,6 +3,7 @@
 
 #include "../typedefs.h"
 #include "Viewport.h"
+#include "../window/Window.h"
 
 class Batch2D;
 
@@ -10,8 +11,10 @@ class GfxContext {
     const GfxContext* parent;
     Viewport& viewport;
     Batch2D* const g2d;
+    bool depthMask_ = true;
     bool depthTest_ = false;
     bool cullFace_ = false;
+    blendmode blendMode_ = blendmode::normal;
 public:
     GfxContext(const GfxContext* parent, Viewport& viewport, Batch2D* g2d);
     ~GfxContext();
@@ -20,8 +23,10 @@ public:
     const Viewport& getViewport() const;
     GfxContext sub() const;
 
+    void depthMask(bool flag);
     void depthTest(bool flag);
     void cullFace(bool flag);
+    void blendMode(blendmode mode);
 };
 
 #endif // GRAPHICS_GFX_CONTEXT_H_

src/graphics/Texture.cpp

@@ -46,6 +46,13 @@ ImageData* Texture::readData() {
     return new ImageData(ImageFormat::rgba8888, width, height, data.release());
 }
 
+void Texture::setNearestFilter() {
+    bind();
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+    glBindTexture(GL_TEXTURE_2D, 0);
+}
+
 Texture* Texture::from(const ImageData* image) {
     uint width = image->getWidth();
     uint height = image->getHeight();

src/graphics/Texture.h

@@ -18,6 +18,8 @@ public:
     void bind();
     void reload(ubyte* data);
 
+    void setNearestFilter();
+
     ImageData* readData();
 
     static Texture* from(const ImageData* image);

src/logic/BlocksController.cpp

@@ -125,9 +125,9 @@ void BlocksController::randomTick(int tickid, int parts) {
                 continue;
             for (int s = 0; s < segments; s++) {
                 for (int i = 0; i < 4; i++) {
-                    int bx = fastmaths::rand() % CHUNK_W;
+                    int bx = random.rand() % CHUNK_W;
-                    int by = fastmaths::rand() % segheight + s * segheight;
+                    int by = random.rand() % segheight + s * segheight;
-                    int bz = fastmaths::rand() % CHUNK_D;
+                    int bz = random.rand() % CHUNK_D;
                     const voxel& vox = chunk->voxels[(by * CHUNK_D + bz) * CHUNK_W + bx];
                     Block* block = indices->getBlockDef(vox.id);
                     if (block->rt.funcsset.randupdate) {

src/logic/BlocksController.h

@@ -2,6 +2,7 @@
 #define LOGIC_BLOCKS_CONTROLLER_H_
 
 #include "../typedefs.h"
+#include "../maths/fastmaths.h"
 
 class Player;
 class Block;
@@ -33,6 +34,7 @@ class BlocksController {
     Clock randTickClock;
     Clock blocksTickClock;
     uint padding;
+    FastRandom random;
 public:
     BlocksController(Level* level, uint padding);
 

src/maths/fastmaths.h

@@ -1,17 +1,23 @@
 #ifndef MATHS_FASTMATHS_H_
 #define MATHS_FASTMATHS_H_
 
-namespace fastmaths {
+#include "../typedefs.h"
-    static unsigned int g_seed;
 
-    inline void srand(int seed) {
+class FastRandom {
-        g_seed = seed;
+    uint seed;
+public:
+    inline void setSeed(uint seed) {
+        this->seed = seed;
     }
 
-    inline int rand(void) {
+    inline int rand() {
-        g_seed = (214013*g_seed+2531011);
+        seed = (214013 * seed + 2531011);
-        return (g_seed>>16)&0x7FFF;
+        return (seed>>16) & 0x7FFF;   
     }
-}
+
+    inline float randFloat() {
+        return rand() / float(0x7FFF);
+    }
+};
 
 #endif // MATHS_FASTMATHS_H_

src/window/Window.cpp

@@ -167,6 +167,17 @@ int Window::initialize(DisplaySettings& settings){
 	return 0;
 }
 
+void Window::setBlendMode(blendmode mode) {
+    switch (mode) {
+        case blendmode::normal:
+            glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+            break;
+        case blendmode::addition:
+            glBlendFunc(GL_SRC_ALPHA, GL_ONE);
+            break;
+    }
+}
+
 void Window::clear() {
 	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 }

src/window/Window.h

@@ -14,6 +14,10 @@ class ImageData;
 struct DisplaySettings;
 struct GLFWmonitor;
 
+enum class blendmode {
+    normal, addition
+};
+
 class Window {
 	static GLFWwindow* window;
 	static DisplaySettings* settings;
@@ -53,6 +57,8 @@ public:
     static const char* getClipboardText();
 	static DisplaySettings* getSettings();
 
+    static void setBlendMode(blendmode mode);
+
 	static glm::vec2 size() {
 		return glm::vec2(width, height);
 	}