| // Copyright (C) 2009 The Android Open Source Project |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| #pragma version(1) |
| #pragma stateVertex(PVBackground) |
| #pragma stateRaster(parent) |
| #pragma stateFragment(PFBackground) |
| #pragma stateFragmentStore(PFSBackground) |
| |
| #define ELLIPSE_RATIO 0.892f |
| |
| #define PI 3.1415f |
| #define TWO_PI 6.283f |
| #define ELLIPSE_TWIST 0.023333333f |
| |
| float angle; |
| float distance; |
| |
| /** |
| * Script initialization. Called automatically. |
| */ |
| void init() { |
| angle = 37.0f; |
| distance = 0.55f; |
| } |
| |
| /** |
| * Helper function to generate the stars. |
| */ |
| float randomGauss() { |
| float x1; |
| float x2; |
| float w = 2.f; |
| |
| while (w >= 1.0f) { |
| x1 = 2.0f * randf2(0.0f, 1.0f) - 1.0f; |
| x2 = 2.0f * randf2(0.0f, 1.0f) - 1.0f; |
| w = x1 * x1 + x2 * x2; |
| } |
| |
| w = sqrtf(-2.0 * logf(w) / w); |
| return x1 * w; |
| } |
| |
| /** |
| * Generates the properties for a given star. |
| */ |
| void createParticle(struct Stars_s *star, struct Particles_s *part, float scale) { |
| float d = fabsf(randomGauss()) * State->galaxyRadius * 0.5f + randf(64.0f); |
| float id = d / State->galaxyRadius; |
| float z = randomGauss() * 0.4f * (1.0f - id); |
| float p = -d * ELLIPSE_TWIST; |
| |
| if (d < State->galaxyRadius * 0.33f) { |
| part->r = (int) (220 + id * 35); |
| part->g = 220; |
| part->b = 220; |
| } else { |
| part->r= 180; |
| part->g = 180; |
| part->b = (int) clampf(140.f + id * 115.f, 140.f, 255.f); |
| } |
| part->a = (int) (140 + (1.0f - id) * 115); |
| |
| if (d > State->galaxyRadius * 0.15f) { |
| z *= 0.6f * (1.0f - id); |
| } else { |
| z *= 0.72f; |
| } |
| |
| // Map to the projection coordinates (viewport.x = -1.0 -> 1.0) |
| d = mapf(-4.0f, State->galaxyRadius + 4.0f, 0.0f, scale, d); |
| |
| star->angle = randf(TWO_PI); |
| star->distance = d; |
| star->speed = randf2(0.0015f, 0.0025f) * (0.5f + (scale / d)) * 0.8f; |
| star->s = cosf(p); |
| star->t = sinf(p); |
| |
| part->z = z / 5.0f; |
| part->pointSize = randf2(1.2f, 2.1f) * 6; |
| } |
| |
| /** |
| * Initialize all the stars. Called from Java. |
| */ |
| void initParticles() { |
| struct Stars_s *star = Stars; |
| struct Particles_s *part = Particles; |
| int particlesCount = State->particlesCount; |
| float scale = State->galaxyRadius / (State->width * 0.5f); |
| |
| int i; |
| for (i = 0; i < particlesCount; i ++) { |
| createParticle(star, part, scale); |
| star++; |
| part++; |
| } |
| } |
| |
| void drawSpace(float xOffset, int width, int height) { |
| bindTexture(NAMED_PFBackground, 0, NAMED_TSpace); |
| drawQuadTexCoords( |
| 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, |
| width, 0.0f, 0.0f, 2.0f, 1.0f, |
| width, height, 0.0f, 2.0f, 0.0f, |
| 0.0f, height, 0.0f, 0.0f, 0.0f); |
| } |
| |
| void drawLights(float xOffset, int width, int height) { |
| bindProgramVertex(NAMED_PVStars); |
| bindProgramFragment(NAMED_PFBackground); |
| bindTexture(NAMED_PFBackground, 0, NAMED_TLight1); |
| |
| float scale = 512.0f / width; |
| float x = -scale + xOffset - scale * 0.05f; |
| float y = -scale; |
| |
| scale *= 2.0f; |
| |
| drawQuad(x, y, 0.0f, |
| x + scale * 1.1f, y, 0.0f, |
| x + scale * 1.1f, y + scale, 0.0f, |
| x, y + scale, 0.0f); |
| } |
| |
| void drawParticles(float xOffset, int width, int height) { |
| bindProgramVertex(NAMED_PVStars); |
| bindProgramFragment(NAMED_PFStars); |
| bindProgramFragmentStore(NAMED_PFSLights); |
| bindTexture(NAMED_PFStars, 0, NAMED_TFlares); |
| |
| float matrix[16]; |
| matrixLoadTranslate(matrix, 0.0f, 0.0f, 10.0f - 6.0f * distance); |
| matrixScale(matrix, 6.6f, 6.0f, 1.0f); |
| matrixRotate(matrix, angle, 1.0f, 0.5f, 0.0f); |
| vpLoadModelMatrix(matrix); |
| |
| // quadratic attenuation |
| pointAttenuation(0.1f, 0.0f, 0.06f); |
| |
| int radius = State->galaxyRadius; |
| int particlesCount = State->particlesCount; |
| |
| struct Stars_s *star = Stars; |
| struct Particles_s *vtx = Particles; |
| |
| int i = 0; |
| for ( ; i < particlesCount; i++) { |
| float a = star->angle + star->speed; |
| float x = star->distance * sinf(a); |
| float y = star->distance * cosf(a) * ELLIPSE_RATIO; |
| |
| vtx->x = star->t * x + star->s * y + xOffset; |
| vtx->y = star->s * x - star->t * y; |
| |
| star->angle = a; |
| |
| star++; |
| vtx++; |
| } |
| |
| uploadToBufferObject(NAMED_ParticlesBuffer); |
| drawSimpleMeshRange(NAMED_ParticlesMesh, 0, particlesCount); |
| } |
| |
| int main(int index) { |
| int width = State->width; |
| int height = State->height; |
| |
| float x = lerpf(1.0f, -1.0f, State->xOffset); |
| |
| drawSpace(x, width, height); |
| drawParticles(x, width, height); |
| drawLights(x, width, height); |
| |
| if (State->isPreview == 0) { |
| if (angle > 0.0f) { |
| angle -= 0.4f; |
| distance = angle / 68.0f; |
| } |
| } else { |
| // Unfortunately this cannot happen in init() |
| // since the State structure instance does not |
| // exist at this point |
| angle = 0.0f; |
| distance = 0.0f; |
| } |
| |
| return 1; |
| } |