res/raw/galaxy.rs

// 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 stateFragment(PFBackground)
#pragma stateFragmentStore(PFSBackground)

#define ELLIPSE_RATIO 0.892f

float angle;
float distance;

void init() {
    angle = 0.0f;
    distance = 0.0f;
}

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, 6.15f, 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;

    float w = xOffset;

    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 + w;
        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 (angle < 68.0f) {
//        angle += 0.4f;
//        distance = angle / 68.0f;
//    }

    return 1;
}