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tutorial: work around i915 driver limitations in the Mandelbrot viewer shader.

legacy
Sam Hocevar sam 13 vuotta sitten
vanhempi
5adaccac91
commit
b5cc7b7877
1 muutettua tiedostoa jossa 155 lisäystä ja 78 poistoa
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  1. +155
    -78
      test/tutorial/tut03.cpp

+ 155
- 78
test/tutorial/tut03.cpp Näytä tiedosto

@@ -56,8 +56,8 @@ public:
m_size = size;
m_size.x = (m_size.x + 15) & ~15;
m_size.y = (m_size.y + 15) & ~15;
m_texel_settings = vec4(vec2(1.0, 1.0) / (vec2)m_size,
vec2(0.5, 0.5) * (vec2)m_size);
m_texel_settings = vec4(1.0, 1.0, 2.0, 2.0) / (vec4)m_size.xyxy();
m_screen_settings = vec4(1.0, 1.0, 0.5, 0.5) * (vec4)m_size.xyxy();

/* Window size decides the world aspect ratio. For instance, 640×480
* will be mapped to (-0.66,-0.5) - (0.66,0.5). */
@@ -78,6 +78,7 @@ public:
m_pixels = new u8vec4[m_size.x * m_size.y];
m_tmppixels = new u8vec4[m_size.x / 2 * m_size.y / 2];
m_frame = -1;
m_slices = 4;
for (int i = 0; i < 4; i++)
{
m_deltashift[i] = 0.0;
@@ -96,6 +97,7 @@ public:
m_translate = 0;
m_radius = 5.0;
m_ready = false;
m_drag = false;

m_palette = new u8vec4[(MAX_ITERATIONS + 1) * PALETTE_STEP];
for (int i = 0; i < (MAX_ITERATIONS + 1) * PALETTE_STEP; i++)
@@ -157,14 +159,14 @@ public:
delete m_palette;
}

inline f64cmplx TexelToWorldOffset(ivec2 texel)
inline f64cmplx TexelToWorldOffset(vec2 texel)
{
double dx = (0.5 + texel.x - m_size.x / 2) * m_texel2world.x;
double dy = (0.5 + m_size.y / 2 - texel.y) * m_texel2world.y;
return m_radius * f64cmplx(dx, dy);
}

inline f64cmplx ScreenToWorldOffset(ivec2 pixel)
inline f64cmplx ScreenToWorldOffset(vec2 pixel)
{
/* No 0.5 offset here, because we want to be able to position the
* mouse at (0,0) exactly. */
@@ -186,17 +188,30 @@ public:
#if !defined __CELLOS_LV2__
if (buttons[1])
{
if (clicked[1])
if (!m_drag)
{
m_oldmouse = mousepos;
m_drag = true;
}
m_translate = ScreenToWorldOffset(m_oldmouse)
- ScreenToWorldOffset(mousepos);
/* XXX: the purpose of this hack is to avoid translating by
* an exact number of pixels. If this were to happen, the step()
* optimisation for i915 cards in our shader would behave
* incorrectly because a quarter of the pixels in the image
* would have tie rankings in the distance calculation. */
m_translate *= 1023.0 / 1024.0;
m_oldmouse = mousepos;
}
else if (m_translate != 0.0)
else
{
m_translate *= pow(2.0, -deltams * 0.005);
if (m_translate.norm() / m_radius < 1e-4)
m_translate = 0.0;
m_drag = false;
if (m_translate != 0.0)
{
m_translate *= pow(2.0, -deltams * 0.005);
if (m_translate.norm() / m_radius < 1e-4)
m_translate = 0.0;
}
}

if ((buttons[0] || buttons[2]) && mousepos.x != -1)
@@ -209,7 +224,7 @@ public:
else if (m_zoom_speed)
{
m_zoom_speed *= pow(2.0, -deltams * 0.005);
if (abs(m_zoom_speed) < 1e-5)
if (abs(m_zoom_speed) < 1e-5 || m_drag)
m_zoom_speed = 0.0;
}
#endif
@@ -286,54 +301,88 @@ public:
m_zoomtext->SetText(buf);
#endif

u8vec4 *m_pixelstart = m_pixels + m_size.x * m_size.y / 4 * m_frame;

if (m_dirty[m_frame])
{
double const maxsqlen = 1024;
double const k1 = 1.0 / (1 << 10) / log2(maxsqlen);

m_dirty[m_frame]--;

for (int j = ((m_frame + 1) % 4) / 2; j < m_size.y; j += 2)
for (int i = m_frame % 2; i < m_size.x; i += 2)
/* FIXME: this is the ugliest, most pathetic excuse for a
* threading system that I have seen in a while. */
DoWorkHelper helpers[m_slices];
for (int slice = 0; slice < m_slices; slice++)
{
helpers[slice].fractal = this;
helpers[slice].slice = slice;
helpers[slice].thread = new Thread(DoWorkHelper::Help,
&helpers[slice]);
}
for (int slice = 0; slice < m_slices; slice++)
{
delete helpers[slice].thread;
}
}
}

struct DoWorkHelper
{
Fractal *fractal;
Thread *thread;
int slice;

static void *Help(void *data)
{
DoWorkHelper *helper = (DoWorkHelper *)data;
helper->fractal->DoWork(helper->slice);
return NULL;
}
};

void DoWork(int slice)
{
double const maxsqlen = 1024;
double const k1 = 1.0 / (1 << 10) / log2(maxsqlen);

int jmin = m_size.y * slice / m_slices;
int jmax = m_size.y * (slice + 1) / m_slices;
u8vec4 *m_pixelstart = m_pixels
+ m_size.x * (m_size.y / 4 * m_frame + jmin / 4);

f64cmplx z0 = m_center + TexelToWorldOffset(ivec2(i, j));
f64cmplx r0 = z0;
//f64cmplx r0(0.28693186889504513, 0.014286693904085048);
//f64cmplx r0(0.001643721971153, 0.822467633298876);
//f64cmplx r0(-1.207205434596, 0.315432814901);
//f64cmplx r0(-0.79192956889854, -0.14632423080102);
//f64cmplx r0(0.3245046418497685, 0.04855101129280834);
f64cmplx z;
int iter = MAX_ITERATIONS;
for (z = z0; iter && z.sqlen() < maxsqlen; z = z * z + r0)
--iter;

if (iter)
{
double f = iter;
double n = z.sqlen();
if (n > maxsqlen * maxsqlen)
n = maxsqlen * maxsqlen;

/* Approximate log(sqrt(n))/log(sqrt(maxsqlen)) */
union { double n; uint64_t x; } u = { n };
double k = (u.x >> 42) - (((1 << 10) - 1) << 10);
k *= k1;

/* Approximate log2(k) in [1,2]. */
f += (- 0.344847817623168308695977510213252644185 * k
+ 2.024664188044341212602376988171727038739) * k
- 1.674876738008591047163498125918330313237;

*m_pixelstart++ = m_palette[(int)(f * PALETTE_STEP)];
}
else
{
*m_pixelstart++ = u8vec4(0, 0, 0, 255);
}
for (int j = ((m_frame + 1) % 4) / 2 + jmin; j < jmax; j += 2)
for (int i = m_frame % 2; i < m_size.x; i += 2)
{
f64cmplx z0 = m_center + TexelToWorldOffset(ivec2(i, j));
f64cmplx r0 = z0;
//f64cmplx r0(0.28693186889504513, 0.014286693904085048);
//f64cmplx r0(0.001643721971153, 0.822467633298876);
//f64cmplx r0(-1.207205434596, 0.315432814901);
//f64cmplx r0(-0.79192956889854, -0.14632423080102);
//f64cmplx r0(0.3245046418497685, 0.04855101129280834);
f64cmplx z;
int iter = MAX_ITERATIONS;
for (z = z0; iter && z.sqlen() < maxsqlen; z = z * z + r0)
--iter;

if (iter)
{
double f = iter;
double n = z.sqlen();
if (n > maxsqlen * maxsqlen)
n = maxsqlen * maxsqlen;

/* Approximate log(sqrt(n))/log(sqrt(maxsqlen)) */
union { double n; uint64_t x; } u = { n };
double k = (u.x >> 42) - (((1 << 10) - 1) << 10);
k *= k1;

/* Approximate log2(k) in [1,2]. */
f += (- 0.344847817623168308695977510213252644185 * k
+ 2.024664188044341212602376988171727038739) * k
- 1.674876738008591047163498125918330313237;

*m_pixelstart++ = m_palette[(int)(f * PALETTE_STEP)];
}
else
{
*m_pixelstart++ = u8vec4(0, 0, 0, 255);
}
}
}
@@ -390,6 +439,7 @@ public:
""
"uniform mat4 u_ZoomSettings;"
"uniform vec4 u_TexelSize;"
"uniform vec4 u_ScreenSize;"
""
"attribute vec2 a_TexCoord;"
"attribute vec2 a_Vertex;"
@@ -418,7 +468,6 @@ public:
" u_ZoomSettings[1][1],"
" u_ZoomSettings[2][1],"
" u_ZoomSettings[3][1]);"
/* Pass all this to the fragment shader */
" v_CenterX = zoomscale * a_TexCoord.x + zoomtx"
" + offsets.xyxy * u_TexelSize.x;"
" v_CenterY = zoomscale * a_TexCoord.y - zoomty"
@@ -427,8 +476,8 @@ public:
* point lies. The fragment shader will call floor() on
* this value. We add or remove a slight offset to avoid
* rounding issues at the image's edges. */
" v_IndexX = v_CenterX * u_TexelSize.z - offsets.zwzw;"
" v_IndexY = v_CenterY * u_TexelSize.w - offsets.zwwz;"
" v_IndexX = v_CenterX * u_ScreenSize.z - (offsets.zwzw + vec4(0.001, 0.002, 0.003, 0.004));"
" v_IndexY = v_CenterY * u_ScreenSize.w - (offsets.zwwz + vec4(0.0015, 0.0025, 0.0035, 0.0045));"
"}",

#if !defined HAVE_GLES_2X
@@ -444,33 +493,59 @@ public:
""
"void main(void)"
"{"
/* Get a pixel coordinate from each slice into rx & ry */
" vec4 rx = u_TexelSize.x * (1.0 + 2.0 * floor(v_IndexX));"
" vec4 ry = u_TexelSize.y * (1.0 + 2.0 * floor(v_IndexY));"
/* Compute distance to expected pixel in dd */
" vec4 v05 = vec4(0.5, 0.5, 0.5, 0.5);"
" vec4 t0 = step(abs(rx - v05), v05)"
" * step(abs(ry - v05), v05);"
" vec4 dx = rx - v_CenterX;"
" vec4 dy = ry - v_CenterY;"
" vec4 rx, ry, t0, dx, dy, dd;"
/* Get a pixel coordinate from each slice into rx & ry */
" rx = u_TexelSize.x + u_TexelSize.z * floor(v_IndexX);"
" ry = u_TexelSize.y + u_TexelSize.w * floor(v_IndexY);"
/* Compute inverse distance to expected pixel in dd,
* and put zero if we fall outside the texture. */
" t0 = step(abs(rx - v05), v05) * step(abs(ry - v05), v05);"
" dx = rx - v_CenterX;"
" dy = ry - v_CenterY;"
//" vec4 dd = t0 * (abs(dx) + abs(dy));"
//" vec4 dd = t0 / (0.001 + sqrt((dx * dx) + (dy * dy)));"
" vec4 dd = t0 / (0.000001 + (dx * dx) + (dy * dy));"
" dd = t0 / (0.000001 + (dx * dx) + (dy * dy));"
/* Modify Y coordinate to select proper quarter. */
" ry = ry * 0.25 + vec4(0.0, 0.25, 0.5, 0.75);"
""
#if 1
/* Put min(.x,.y) in .x and min(.z,.w) in .z */
" vec4 t1 = step(dd, dd.yyww);"
" rx = mix(rx, rx.yyww, t1);"
" ry = mix(ry, ry.yyww, t1);"
" dd = mix(dd, dd.yyww, t1);"
/* Put min(x,z) in x */
" vec4 t2 = step(dd, dd.zzzz);"
" rx = mix(rx, rx.zzzz, t2);"
" ry = mix(ry, ry.zzzz, t2);"
"\n#if 0\n" /* XXX: disabled until we can autodetect i915 */
/* t1.x <-- dd.x > dd.y */
/* t1.y <-- dd.z > dd.w */
" vec2 t1 = step(dd.xz, dd.yw);"
/* ret.x <-- max(rx.x, rx.y) wrt. t1.x */
/* ret.y <-- max(rx.z, rx.w) wrt. t1.y */
/* ret.z <-- max(ry.x, ry.y) wrt. t1.x */
/* ret.w <-- max(ry.z, ry.w) wrt. t1.y */
" vec4 ret = mix(vec4(rx.xz, ry.xz),"
" vec4(rx.yw, ry.yw), t1.xyxy);"
/* dd.x <-- max(dd.x, dd.y) */
/* dd.z <-- max(dd.z, dd.w) */
" dd.xy = mix(dd.xz, dd.yw, t1);"
/* t2 <-- dd.x > dd.z */
" float t2 = step(dd.x, dd.y);"
/* ret.x <-- max(ret.x, ret.y); */
/* ret.y <-- max(ret.z, ret.yw; */
" ret.xy = mix(ret.xz, ret.yw, t2);"
"\n#else\n"
/* Fallback for i915 cards -- the trick to reduce the
* number of operations is to compute both step(a,b)
* and step(b,a) and hope that their sum is 1. This is
* almost always the case, and when it isn't we can
* afford to have a few wrong pixels. However, a real
* problem is when panning the image, because half the
* screen is likely to flicker. To avoid this problem,
* we cheat a little (see m_translate comment above). */
" vec4 t1 = step(dd.xzyw, dd.ywxz);"
" vec4 ret = vec4(rx.xz, ry.xz) * t1.zwzw"
" + vec4(rx.yw, ry.yw) * t1.xyxy;"
" dd.xy = dd.xz * t1.zw + dd.yw * t1.xy;"
" vec2 t2 = step(dd.xy, dd.yx);"
" ret.xy = ret.xz * t2.yy + ret.yw * t2.xx;"
"\n#endif\n"
/* Nearest neighbour */
" gl_FragColor = texture2D(in_Texture, vec2(rx.x, ry.x));"
" gl_FragColor = texture2D(in_Texture, ret.xy);"
#else
/* Alternate version: some kind of linear interpolation */
" vec4 p0 = texture2D(in_Texture, vec2(rx.x, ry.x));"
@@ -545,6 +620,7 @@ public:
m_vertexattrib = m_shader->GetAttribLocation("a_Vertex");
m_texattrib = m_shader->GetAttribLocation("a_TexCoord");
m_texeluni = m_shader->GetUniformLocation("u_TexelSize");
m_screenuni = m_shader->GetUniformLocation("u_ScreenSize");
m_zoomuni = m_shader->GetUniformLocation("u_ZoomSettings");
m_ready = true;

@@ -591,6 +667,7 @@ public:

m_shader->Bind();
m_shader->SetUniform(m_texeluni, m_texel_settings);
m_shader->SetUniform(m_screenuni, m_screen_settings);
m_shader->SetUniform(m_zoomuni, m_zoom_settings);
#if !defined __CELLOS_LV2__ && !defined __ANDROID__
glBindBuffer(GL_ARRAY_BUFFER, m_vbo);
@@ -641,13 +718,13 @@ private:
GLuint m_vbo, m_tbo;
GLuint m_tco;
#endif
int m_vertexattrib, m_texattrib, m_texeluni, m_zoomuni;
int m_frame, m_dirty[4];
bool m_ready;
int m_vertexattrib, m_texattrib, m_texeluni, m_screenuni, m_zoomuni;
int m_frame, m_slices, m_dirty[4];
bool m_ready, m_drag;

f64cmplx m_center, m_translate;
double m_zoom_speed, m_radius;
vec4 m_texel_settings;
vec4 m_texel_settings, m_screen_settings;
mat4 m_zoom_settings;
f64cmplx m_deltashift[4];
double m_deltascale[4];


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