Sprite: Implement wave effect (RGSS2)

This initial implementation emulates the way RMVX splits
the sprite into "chunks" of about 8 pixels, which it then
scrolls left/right on a vertical sine wave. It even
replicates the weird behavior when wave_amp < 0, namely
"shrinking" the src_rect horizontally.

As with bush_opacity, this effect in combination with
rotation will render differently from RMVX.

binding-mri/sprite-binding.cpp

@@ -69,6 +69,39 @@ DEF_PROP_F(Sprite, Angle)
 
 DEF_PROP_B(Sprite, Mirror)
 
+#ifdef RGSS2
+
+RB_METHOD(spriteWidth)
+{
+	RB_UNUSED_PARAM;
+
+	Sprite *s = getPrivateData<Sprite>(self);
+
+	int value;
+	GUARD_EXC( value = s->getWidth(); )
+
+	return rb_fix_new(value);
+}
+
+RB_METHOD(spriteHeight)
+{
+	RB_UNUSED_PARAM;
+
+	Sprite *s = getPrivateData<Sprite>(self);
+
+	int value;
+	GUARD_EXC( value = s->getHeight(); )
+
+	return rb_fix_new(value);
+}
+
+DEF_PROP_I(Sprite, WaveAmp)
+DEF_PROP_I(Sprite, WaveLength)
+DEF_PROP_I(Sprite, WaveSpeed)
+DEF_PROP_F(Sprite, WavePhase)
+
+#endif
+
 void
 spriteBindingInit()
 {
@@ -98,4 +131,14 @@ spriteBindingInit()
 	INIT_PROP_BIND( Sprite, BlendType, "blend_type" );
 	INIT_PROP_BIND( Sprite, Color,     "color"      );
 	INIT_PROP_BIND( Sprite, Tone,      "tone"       );
+
+#ifdef RGSS2
+	_rb_define_method(klass, "width", spriteWidth);
+	_rb_define_method(klass, "height", spriteHeight);
+
+	INIT_PROP_BIND( Sprite, WaveAmp,    "wave_amp"    );
+	INIT_PROP_BIND( Sprite, WaveLength, "wave_length" );
+	INIT_PROP_BIND( Sprite, WaveSpeed,  "wave_speed"  );
+	INIT_PROP_BIND( Sprite, WavePhase,  "wave_phase"  );
+#endif
 }

binding-mruby/sprite-binding.cpp

@@ -68,6 +68,35 @@ DEF_PROP_F(Sprite, Angle)
 
 DEF_PROP_B(Sprite, Mirror)
 
+#ifdef RGSS2
+
+MRB_METHOD(spriteWidth)
+{
+	Sprite *s = getPrivateData<Sprite>(mrb, self);
+
+	int value;
+	GUARD_EXC( value = s->getWidth(); )
+
+	return mrb_fixnum_value(value);
+}
+
+MRB_METHOD(spriteHeight)
+{
+	Sprite *s = getPrivateData<Sprite>(mrb, self);
+
+	int value;
+	GUARD_EXC( value = s->getHeight(); )
+
+	return mrb_fixnum_value(value);
+}
+
+DEF_PROP_I(Sprite, WaveAmp)
+DEF_PROP_I(Sprite, WaveLength)
+DEF_PROP_I(Sprite, WaveSpeed)
+DEF_PROP_F(Sprite, WavePhase)
+
+#endif
+
 void
 spriteBindingInit(mrb_state *mrb)
 {
@@ -95,5 +124,15 @@ spriteBindingInit(mrb_state *mrb)
 	INIT_PROP_BIND( Sprite, Color,     "color"      );
 	INIT_PROP_BIND( Sprite, Tone,      "tone"       );
 
+#ifdef RGSS2
+	mrb_define_method(mrb, klass, "width",  spriteWidth,  MRB_ARGS_NONE());
+	mrb_define_method(mrb, klass, "height", spriteHeight, MRB_ARGS_NONE());
+
+	INIT_PROP_BIND( Sprite, WaveAmp,    "wave_amp"    );
+	INIT_PROP_BIND( Sprite, WaveLength, "wave_length" );
+	INIT_PROP_BIND( Sprite, WaveSpeed,  "wave_speed"  );
+	INIT_PROP_BIND( Sprite, WavePhase,  "wave_phase"  );
+#endif
+
 	mrb_define_method(mrb, klass, "inspect", inspectObject, MRB_ARGS_NONE());
 }

src/flashable.h

@@ -55,7 +55,7 @@ public:
 		flashAlpha = flashColor.w;
 	}
 
-	void update()
+	virtual void update()
 	{
 		if (!flashing)
 			return;

src/quadarray.h

@@ -34,17 +34,41 @@
 typedef uint32_t index_t;
 #define _GL_INDEX_TYPE GL_UNSIGNED_INT
 
-struct ColorQuadArray
+/* A small hack to get mutable QuadArray constructors */
+inline void initBufferBindings(Vertex *)
 {
-	std::vector<Vertex> vertices;
+	glEnableVertexAttribArray(Shader::Color);
+	glEnableVertexAttribArray(Shader::Position);
+	glEnableVertexAttribArray(Shader::TexCoord);
+
+	glVertexAttribPointer(Shader::Color,    4, GL_FLOAT, GL_FALSE, sizeof(Vertex), Vertex::colorOffset());
+	glVertexAttribPointer(Shader::Position, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), Vertex::posOffset());
+	glVertexAttribPointer(Shader::TexCoord, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), Vertex::texPosOffset());
+}
+
+inline void initBufferBindings(SVertex *)
+{
+	glEnableVertexAttribArray(Shader::Position);
+	glEnableVertexAttribArray(Shader::TexCoord);
+
+	glVertexAttribPointer(Shader::Position, 2, GL_FLOAT, GL_FALSE, sizeof(SVertex), SVertex::posOffset());
+	glVertexAttribPointer(Shader::TexCoord, 2, GL_FLOAT, GL_FALSE, sizeof(SVertex), SVertex::texPosOffset());
+}
+
+template<class VertexType>
+struct QuadArray
+{
+	std::vector<VertexType> vertices;
 
 	VBO::ID vbo;
 	VAO::ID vao;
 
 	int quadCount;
+	GLsizeiptr vboSize;
 
-	ColorQuadArray()
+	QuadArray()
-	    : quadCount(0)
+	    : quadCount(0),
+	      vboSize(-1)
 	{
 		vbo = VBO::gen();
 		vao = VAO::gen();
@@ -53,20 +77,16 @@ struct ColorQuadArray
 		VBO::bind(vbo);
 		shState->bindQuadIBO();
 
-		glEnableVertexAttribArray(Shader::Color);
+		/* Call correct implementation here via overloading */
-		glEnableVertexAttribArray(Shader::Position);
+		VertexType *dummy = 0;
-		glEnableVertexAttribArray(Shader::TexCoord);
+		initBufferBindings(dummy);
-
-		glVertexAttribPointer(Shader::Color,    4, GL_FLOAT, GL_FALSE, sizeof(Vertex), Vertex::colorOffset());
-		glVertexAttribPointer(Shader::Position, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), Vertex::posOffset());
-		glVertexAttribPointer(Shader::TexCoord, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), Vertex::texPosOffset());
 
 		VAO::unbind();
 		IBO::unbind();
 		VBO::unbind();
 	}
 
-	~ColorQuadArray()
+	~QuadArray()
 	{
 		VBO::del(vbo);
 		VAO::del(vao);
@@ -78,15 +98,36 @@ struct ColorQuadArray
 		quadCount = size;
 	}
 
+	void clear()
+	{
+		vertices.clear();
+		quadCount = 0;
+	}
+
 	/* This needs to be called after the final 'append()' call
 	 * and previous to the first 'draw()' call. */
 	void commit()
 	{
 		VBO::bind(vbo);
-		VBO::uploadData(vertices.size() * sizeof(Vertex), &vertices[0], GL_DYNAMIC_DRAW);
-		VBO::unbind();
 
-		shState->ensureQuadIBO(quadCount);
+		GLsizeiptr size = vertices.size() * sizeof(VertexType);
+
+		if (size > vboSize)
+		{
+			/* New data exceeds already allocated size.
+			 * Reallocate VBO. */
+			VBO::uploadData(size, &vertices[0], GL_DYNAMIC_DRAW);
+			vboSize = size;
+
+			shState->ensureQuadIBO(quadCount);
+		}
+		else
+		{
+			/* New data fits in allocated size */
+			VBO::uploadSubData(0, size, &vertices[0]);
+		}
+
+		VBO::unbind();
 	}
 
 	void draw(size_t offset, size_t count)
@@ -110,4 +151,7 @@ struct ColorQuadArray
 	}
 };
 
+typedef QuadArray<Vertex> ColorQuadArray;
+typedef QuadArray<SVertex> SimpleQuadArray;
+
 #endif // QUADARRAY_H

src/sprite.cpp

@@ -32,6 +32,9 @@
 #include "transform.h"
 #include "shader.h"
 #include "glstate.h"
+#include "quadarray.h"
+
+#include <math.h>
 
 #include <SDL_rect.h>
 
@@ -63,6 +66,22 @@ struct SpritePrivate
 	Color *color;
 	Tone *tone;
 
+#ifdef RGSS2
+	struct
+	{
+		int amp;
+		int length;
+		int speed;
+		float phase;
+
+		/* Wave effect is active (amp != 0) */
+		bool active;
+		/* qArray needs updating */
+		bool dirty;
+		SimpleQuadArray qArray;
+	} wave;
+#endif
+
 	EtcTemps tmp;
 
 	sigc::connection prepareCon;
@@ -87,6 +106,13 @@ struct SpritePrivate
 
 		prepareCon = shState->prepareDraw.connect
 		        (sigc::mem_fun(this, &SpritePrivate::prepare));
+
+#ifdef RGSS2
+		wave.amp = 0;
+		wave.length = 180;
+		wave.speed = 360;
+		wave.phase = 0.0;
+#endif
 	}
 
 	~SpritePrivate()
@@ -117,6 +143,10 @@ struct SpritePrivate
 
 		quad.setPosRect(IntRect(0, 0, srcRect->width, srcRect->height));
 		recomputeBushDepth();
+
+#ifdef RGSS2
+		wave.dirty = true;
+#endif
 	}
 
 	void updateSrcRectCon()
@@ -141,6 +171,16 @@ struct SpritePrivate
 		if (!opacity)
 			return;
 
+#ifdef RGSS2
+		if (wave.active)
+		{
+			/* Don't do expensive wave bounding box
+			 * calculations */
+			isVisible = true;
+			return;
+		}
+#endif
+
 		/* Compare sprite bounding box against the scene */
 
 		/* If sprite is zoomed/rotated, just opt out for now
@@ -161,8 +201,102 @@ struct SpritePrivate
 		isVisible = SDL_HasIntersection(&self, &sceneRect);
 	}
 
+#ifdef RGSS2
+	void emitWaveChunk(SVertex *&vert, float phase, int width,
+	                   float zoomY, int chunkY, int chunkLength)
+	{
+		float wavePos = phase + (chunkY / (float) wave.length) * M_PI * 2;
+		float chunkX = sin(wavePos) * wave.amp;
+
+		FloatRect tex(0, chunkY / zoomY, width, chunkLength / zoomY);
+		FloatRect pos = tex;
+		pos.x = chunkX;
+
+		Quad::setTexPosRect(vert, tex, pos);
+		vert += 4;
+	}
+
+	void updateWave()
+	{
+		if (!bitmap)
+			return;
+
+		if (wave.amp == 0)
+		{
+			wave.active = false;
+			return;
+		}
+
+		wave.active = true;
+
+		int width = srcRect->width;
+		int height = srcRect->height;
+		float zoomY = trans.getScale().y;
+
+		if (wave.amp < -(width / 2))
+		{
+			wave.qArray.resize(0);
+			wave.qArray.commit();
+
+			return;
+		}
+
+		/* RMVX does this, and I have no fucking clue why */
+		if (wave.amp < 0)
+		{
+			wave.qArray.resize(1);
+
+			int x = -wave.amp;
+			int w = width - x * 2;
+
+			FloatRect tex(x, srcRect->y, w, srcRect->height);
+
+			Quad::setTexPosRect(&wave.qArray.vertices[0], tex, tex);
+			wave.qArray.commit();
+
+			return;
+		}
+
+		/* The length of the sprite as it appears on screen */
+		int visibleLength = height * zoomY;
+
+		/* First chunk length (aligned to 8 pixel boundary */
+		int firstLength = ((int) trans.getPosition().y) % 8;
+
+		/* Amount of full 8 pixel chunks in the middle */
+		int chunks = (visibleLength - firstLength) / 8;
+
+		/* Final chunk length */
+		int lastLength = (visibleLength - firstLength) % 8;
+
+		wave.qArray.resize(!!firstLength + chunks + !!lastLength);
+		SVertex *vert = &wave.qArray.vertices[0];
+
+		float phase = (wave.phase * M_PI) / 180.f;
+
+		if (firstLength > 0)
+			emitWaveChunk(vert, phase, width, zoomY, 0, firstLength);
+
+		for (int i = 0; i < chunks; ++i)
+			emitWaveChunk(vert, phase, width, zoomY, firstLength + i * 8, 8);
+
+		if (lastLength > 0)
+			emitWaveChunk(vert, phase, width, zoomY, firstLength + chunks * 8, lastLength);
+
+		wave.qArray.commit();
+	}
+#endif
+
 	void prepare()
 	{
+#ifdef RGSS2
+		if (wave.dirty)
+		{
+			updateWave();
+			wave.dirty = false;
+		}
+#endif
+
 		updateVisibility();
 	}
 };
@@ -193,14 +327,21 @@ DEF_ATTR_RD_SIMPLE(Sprite, Angle,     float,   p->trans.getRotation())
 DEF_ATTR_RD_SIMPLE(Sprite, Mirror,    bool,    p->mirrored)
 DEF_ATTR_RD_SIMPLE(Sprite, BushDepth, int,     p->bushDepth)
 DEF_ATTR_RD_SIMPLE(Sprite, BlendType, int,     p->blendType)
-DEF_ATTR_RD_SIMPLE(Sprite, Width,     int,     p->srcRect->width)
-DEF_ATTR_RD_SIMPLE(Sprite, Height,    int,     p->srcRect->height)
 
 DEF_ATTR_SIMPLE(Sprite, BushOpacity, int,    p->bushOpacity)
 DEF_ATTR_SIMPLE(Sprite, Opacity,     int,    p->opacity)
 DEF_ATTR_SIMPLE(Sprite, Color,       Color*, p->color)
 DEF_ATTR_SIMPLE(Sprite, Tone,        Tone*,  p->tone)
 
+#ifdef RGSS2
+DEF_ATTR_RD_SIMPLE(Sprite, Width,      int,   p->srcRect->width)
+DEF_ATTR_RD_SIMPLE(Sprite, Height,     int,   p->srcRect->height)
+DEF_ATTR_RD_SIMPLE(Sprite, WaveAmp,    int,   p->wave.amp)
+DEF_ATTR_RD_SIMPLE(Sprite, WaveLength, int,   p->wave.length)
+DEF_ATTR_RD_SIMPLE(Sprite, WaveSpeed,  int,   p->wave.speed)
+DEF_ATTR_RD_SIMPLE(Sprite, WavePhase,  float, p->wave.phase)
+#endif
+
 void Sprite::setBitmap(Bitmap *bitmap)
 {
 	GUARD_DISPOSED
@@ -218,6 +359,10 @@ void Sprite::setBitmap(Bitmap *bitmap)
 	*p->srcRect = bitmap->rect();
 	p->onSrcRectChange();
 	p->quad.setPosRect(p->srcRect->toFloatRect());
+
+#ifdef RGSS2
+	p->wave.dirty = true;
+#endif
 }
 
 void Sprite::setSrcRect(Rect *rect)
@@ -252,6 +397,10 @@ void Sprite::setY(int value)
 		return;
 
 	p->trans.setPosition(Vec2(getX(), value));
+
+#ifdef RGSS2
+	p->wave.dirty = true;
+#endif
 }
 
 void Sprite::setOX(int value)
@@ -293,6 +442,10 @@ void Sprite::setZoomY(float value)
 
 	p->trans.setScale(Vec2(getZoomX(), value));
 	p->recomputeBushDepth();
+
+#ifdef RGSS2
+	p->wave.dirty = true;
+#endif
 }
 
 void Sprite::setAngle(float value)
@@ -346,6 +499,36 @@ void Sprite::setBlendType(int type)
 	}
 }
 
+#ifdef RGSS2
+
+#define DEF_WAVE_SETTER(Name, name, type) \
+	void Sprite::setWave##Name(type value) \
+	{ \
+		GUARD_DISPOSED; \
+		if (p->wave.name == value) \
+			return; \
+		p->wave.name = value; \
+		p->wave.dirty = true; \
+	}
+
+DEF_WAVE_SETTER(Amp,    amp,    int)
+DEF_WAVE_SETTER(Length, length, int)
+DEF_WAVE_SETTER(Speed,  speed,  int)
+DEF_WAVE_SETTER(Phase,  phase,  float)
+
+#undef DEF_WAVE_SETTER
+
+/* Flashable */
+void Sprite::update()
+{
+	Flashable::update();
+
+	p->wave.phase += p->wave.speed / 180;
+	p->wave.dirty = true;
+}
+
+#endif
+
 /* Disposable */
 void Sprite::releaseResources()
 {
@@ -407,7 +590,14 @@ void Sprite::draw()
 
 	p->bitmap->bindTex(*base);
 
+#ifdef RGSS2
+	if (p->wave.active)
+		p->wave.qArray.draw();
+	else
+		p->quad.draw();
+#else
 	p->quad.draw();
+#endif
 
 	glState.blendMode.pop();
 }

src/sprite.h

@@ -41,9 +41,6 @@ public:
 	Sprite(Viewport *viewport = 0);
 	~Sprite();
 
-	int getWidth()  const;
-	int getHeight() const;
-
 	DECL_ATTR( Bitmap,      Bitmap* )
 	DECL_ATTR( SrcRect,     Rect*   )
 	DECL_ATTR( X,           int     )
@@ -61,6 +58,18 @@ public:
 	DECL_ATTR( Color,       Color*  )
 	DECL_ATTR( Tone,        Tone*   )
 
+#ifdef RGSS2
+	int getWidth()  const;
+	int getHeight() const;
+
+	DECL_ATTR( WaveAmp,    int   )
+	DECL_ATTR( WaveLength, int   )
+	DECL_ATTR( WaveSpeed,  int   )
+	DECL_ATTR( WavePhase,  float )
+
+	void update();
+#endif
+
 private:
 	SpritePrivate *p;